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Comparison of neonicotinoid insecticides as synergists for entomopathogenic nematodes
Abstract
In previous greenhouse and field studies, the neonicotinoid insecticide imidacloprid and the entomopathogenic nematodes Heterorhabditis bacteriophora and Steinernema glaseri interacted synergistically against third-instars of the Japanese beetle, Popillia japonica, the oriental beetle, Exomala (=Anomala) orientalis, and three masked chafer species, Cyclocephala hirta, C. pasadenae, and C. borealis (Coleoptera: Scarabaeidae). We tested whether this interaction would also occur with other neonicotinoids, primarily thiamethoxam. In laboratory, greenhouse and field experiments, imidacloprid provided stronger and more consistent synergism with nematodes than thiamethoxam. White grub mortality resulting from nematode–neonicotinoid combinations was synergistic/additive/antagonistic in 75/25/0% of our observations with imidacloprid and 37/42/21% of our observations with thiamethoxam. Neonicotinoid–nematode interactions varied with white grub species. Imidacloprid always interacted synergistically with nematodes against E. orientalis and P. japonica, whereas no enhancement occurred against Rhizotrogus majalis and Maladera castanea. Against E. orientalis, imidacloprid interacted synergistically with five nematode species, H. bacteriophora, H. megidis, H. marelatus, S. glaseri, and S. feltiae. Synergistic combinations of nematodes and a neonicotinoid insecticide could be used for curative treatments of white grub infestations, especially against E. orientalis and P. japonica. This combination may allow spot-treatment of turf areas that exceed damage thresholds, thereby limiting the environmental impact of the insecticide application.
... Previous studies have indicated that EPN are compatible with different kinds of chemical insecticides, and some insecticides have been reported to be synergistic with EPN against white grub (Holotrichia oblita, Popillia japonica, Exomala (Anomala) orientalis, Cyclocephala spp., etc), whitefly, (Bemisia tabaci) and leafminer (Liriomyza huidobrensis, Tuta absoluta) [15][16][17][18][19][20][21][22][23][24][25][26][27]. The effect of S. feltiae SN with thiamethoxam to control B. odoriphaga was studied in chive fields in Tai'an, China [28]. ...
... Imidacloprid belongs to a neonicotinoid, and it is a systemic insecticide that acts as an insect neurotoxin. Imidacloprid was widely used in pest control because of its high efficacy, relatively low vertebrae toxicity, low application rates, and long systemic persistence [21]. Imidacloprid was reported to interact synergistically with H. bacteriophora, H. megidis, H. marclatus, S. glaseri, and S. feltiae against different species of white grub [21,33,34] and sweet potato whitefly [17]. ...
... Imidacloprid was widely used in pest control because of its high efficacy, relatively low vertebrae toxicity, low application rates, and long systemic persistence [21]. Imidacloprid was reported to interact synergistically with H. bacteriophora, H. megidis, H. marclatus, S. glaseri, and S. feltiae against different species of white grub [21,33,34] and sweet potato whitefly [17]. Synergistic interactions were not found between H. indica LN2 and imidacloprid against B. odoriphaga in this study. ...
Bradysia odoriphaga is a major pest that causes damage to chive production, and which has developed resistance to highly toxic chemical insecticides. Entomopathogenic nematodes (EPN) show a high potential for B. odoriphaga control. This study aimed to develop an effective management method against B. odoriphaga larvae, using EPN with low-toxicity insecticides. Fourteen selected insecticides had no significant effects on the survival and infectivity of Steinernema feltiae SN and Heterorhabditis indica LN2. Synergistic interactions were observed for imidacloprid and osthole with S. feltiae SN against B. odoriphaga larvae. Steinernema feltiae SN was more effective than H. indica LN2 against B. odoriphaga at 15 and 20 °C, and the addition of imidacloprid at 1/10 recommended concentration (RC) significantly increased the efficacy of S. feltiae SN. The year-round occurrence of the B. odoriphaga larvae in chive fields treated by EPN and imidacloprid at 1/10 RC was studied. Results showed that the application of EPN with imidacloprid at 1/10 RC successfully suppressed larval populations of B. odoriphaga in chive fields, thus significantly increasing the yield of chive. The practical method of applying EPN-imidacloprid combinations provided a cost-effective and environmental safety strategy for controlling B. odoriphaga larvae in chive production, which can reduce the usage of toxic chemical insecticides.
... Among the chemical control methods tested for use on the AGB, the neonicotinoids acetamiprid and imidacloprid have been found ineffective against AGB larvae (Koppenhöfer et al., 2002;Koppenhöfer & Fuzy, 2003a;Morales-Rodriguez et al., 2010). Also ineffective are bifenthrin, a pyrethroid; carbaryl, a carbamate; and halofenozide, a molt-accelerator (Koppenhöfer et al., 2003;Koppenhöfer & Fuzy, 2003a). ...
... Bifenthrin-and halofenozide-treated turf even had higher numbers of third instar grubs than control turf in one experiment (Koppenhöfer et al., 2003). Conflicting results have been reported regarding the effectiveness of the neonicotinoid thiamethoxam against AGB larvae (Koppenhöfer et al., 2002;Koppenhöfer & Fuzy 2003a;Morales-Rodriguez et al., 2010). ...
... The control of adult beetles is especially difficult, however, because AGB adults are strong fliers: when there is a large population nearby, beetles that are killed can quickly be replaced (Hallock, 1932(Hallock, , 1936b (Khan et al., 1976;Koppenhöfer et al., 2002;Koppenhöfer et al., 2006;Koppenhöfer & Fuzy, 2003a;Morales-Rodriguez et al., 2010). ...
The Asiatic garden beetle (AGB), Maladera castanea Arrow, is an invasive pest of crops, ornamentals, and turfgrass that has been minimally studied since the 1930s. Experiments were performed in 2011 and 2012 to investigate adult AGB feeding preferences and seasonality in Connecticut, with the goal of supporting informed planting and monitoring decisions. A common garden field experiment involved counting beetles on three cultivars each of basil, beet, carrot, eggplant, kohlrabi, parsnip, hot pepper, sweet pepper, and turnip. A no-choice laboratory experiment produced values of mass and area of leaf disks consumed. This included the same basil, beet, and kohlrabi varieties in 2011, and elderberry, arrowwood viburnum, green ash, red maple, sugar maple, and American sweetgum in 2012. Counts of beetles collected in light traps were performed throughout each field season. Basil harbored the most AGBs in the field experiment in 2011 and 2012, and was most consumed in the laboratory experiment using edibles in 2012. However, the 2011 laboratory mass data showed that beets were more consumed than kohlrabi, and basil was consumed equally to beets and kohlrabi. In the 2011 field experiment, ‘Mexican Spice’ was preferred over ‘Lemon’ basil. Red maple was significantly more consumed than sugar maple in the laboratory study of ornamentals. In 2012, the first AGB adults were caught on June 20. Peak populations of adult AGBs in Connecticut occurred from mid-July to late August. This study has developed methods and outlined further lines of research on the AGB.
... The EPN concentrations were chosen based on previous studies (Ebssa et al., 2001;Ebssa et al., 2003;Premachandra et al., 2003;Kashkouli et al., 2014). (Koppenhofer et al., 2000b;Koppenhofer et al., 2002). ...
... S. carpocapsae application at 1000 IJs/cm 2 caused significant higher thrips mortality than 400 IJs/cm 2 ( showed high susceptibility to EPNs (Fig. 1). Many studies have assessed the compatibility and the tank-mixing potential of agrochemicals with EPN species (Head et al., 2000;Krishnayyaand and Grewal, 2002;De Nardo and Grewal, 2003;Alumai and Grewal, 2004 (Koppenhofer et al., 2002). ...
Entomopathogenic nematode (EPN) combinations with other control agents are applied to obtain more desirable control of a pest by additive or synergistic effects on the pest mortality. In this study, the potential of EPNs (Steinernema carpocapsae, and Heterorhabditis bacteriophora) alone, chemical insecticides (imidacloprid, deltamethrin, and abamectin) alone, and EPN-insecticide combinations, against the onion thrips, Thrips tabaci (Thysanoptera: Thripidae) was investigated. In the first experiments, the effects of different concentrations of insecticides and EPNs on the thrips larvae were tested and the LC 10 and LC 30 values of insecticides were calculated. Then using a pre-treatment bioassay, the thrips larvae were treated with the EPNs at two concentrations, 400 or 1000 infective juveniles (IJs) per cm 2 , after they had been exposed to LC 30 of abamectin (5.16 mg per litre (l), LC 10 of imidacloprid (50.16 mg/l), or LC 10 of deltamethrin (10.28 mg/l). Mortality percentages were recorded at different time intervals, 24, 48 and 72 hours after the EPNs utilization. Results showed that the sole application of EPNs caused less than 30% thrips mortality. The combination of H. bacteriophora and all insecticides interacted additively on the thrips mortality whereas imidacloprid treatment showed adverse effects on the efficacy of H. bacteriophora at 1000 IJs/cm 2. Additive and synergistic interactions resulted in combining insecticides with S. carpocapsae. These combinations gave mostly higher thrips mortality than with EPN alone and synergistic interactions were observed in S. carpocapsae application at 400 IJs/cm2 with imidacloprid and deltamethrin and also at 1000 IJs/cm 2 with abamectin
... Among different developmental stages of the thrips, prepupal and pupal stages are more sensitive to EPNs than larvae. One explanation for this is low mobility of prepupae and pupae that facilitates nematode attachment to them (Koppenhofer et al., 2002). Prepupae and pupae are quiescent, nonfeeding, and inactive instars (Moritz, 1997) that significantly when the thrips had been fed on green bean or onion (F= 21.45, df= 1, P= 0.0098) ( Figure 2). ...
... Among different developmental stages of the thrips, prepupal and pupal stages are more sensitive to EPNs than larvae. One explanation for this is low mobility of prepupae and pupae that facilitates nematode attachment to them (Koppenhofer et al., 2002). Prepupae and pupae are quiescent, nonfeeding, and inactive instars (Moritz, 1997) that move only when disturbed. ...
The biocontrol potential of entomopathogenic nematodes (EPNs) against soil-dwelling life stages of the onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae) was evaluated under laboratory and semi-field conditions. The pathogenicity of native isolate of Steinernema feltiae (T1) and three commercial strains, S. feltiae, S. carpocapsae (Rhabditida: Steinernematidae) and Heterorhabditis bacteriophora (Rhabditidae: Heterorhabditidae) were tested at concentrations of 400 and 1000 infective juveniles (IJs)/cm 2 against the second instar larvae (L2), prepupae and pupae of the thrips. This was followed with trials compared efficacy of S. carpocapsae on the thrips fed on different host plants, i.e. onion shoots, Allium cepa (L.), pods of green beans, Phaseolus vulgaris (L.) and cucumber fruits, Cucumis sativus (L.). In the semi-field experiments, effects of two EPNs, S. carpocapsae and H. bacteriophora, at concentrations of 10 4 or 2×10 4 IJs/ml against the thrips larval stage were tested. Our results showed that the highest onion thrips corrected mortality (CM) was recorded for prepupae (92%) and pupae (92.59%) at 1000 IJs/cm 2 by S. feltiae (T1) and S. carpocapsae, respectively and the mortality caused by the commercial strain of S. feltiae against thrips larval stage at 400 IJs/cm 2 was the lowest rate (CM= 3.7%). Among different host plants, green bean feeding induced the highest CM by S. carpocapsae at 1000 IJs/cm 2 against the onion thrips larvae. In the semi-field experiments, application of two concentrations of EPNs had no significant effect on the larval mortality, compared to the control treatment.
... They offer distinct advantages over chemical control agents. EPNs have gained recognition as effective biocontrol agents against the larval stages of white grubs (Koppenhöfer et al., 2002). Importantly, EPNs are harmless to plants and vertebrates, and despite their extensive application in fields, gardens, and pastures worldwide, there have been no significant findings of acute or chronic toxicity to humans or other vertebrate populations (Poinar G.O. Jr. et al., 1982& Boemare N.E. ...
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... Seasonal reuse is, therefore, frequently required. Nonetheless, across a number of seasons or years, successful control has occasionally been documented (Koppenhöfer et al., 2002;McCoy et al., 2000). On EPN applications, biotic agents may have favorable, unfavorable, or neutral impacts. ...
An essential part of managing insect pests is the use of entomopathogenic nematodes and in preventing environmental contamination. Their use has been increasing in recent years. So far, about 30 to 40 nematode families are in contact with insects and other vertebrates. Among these families, the group widely studied as the so-called "entomopathogenic nematodes," also known as EPN, are Heterorhabditidae and Steinernematidae. Two species of Oscheius (Oscheius chongmingensis and Oscheius carolinensis) have been added in recent years to the EPNs group, and we expect that several species will be added to EPNs. ENP has a wide range of host insects found in a species of EPN that can attack over 250 different kinds of insects from several families. Suitable environments for EPNs include insect hemocoels, soil pores, or river bottoms that grow in contact with these environments. Occurrence, mobility, distribution, and stability of EPN under the influence of several factors, including intrinsic factors such as behavioral, physiological, and genetic characteristics. Biological nature included are hosted and non-host arthropods, predators, parasites, diseases, and aberrant environmental elements like temperature, moisture content, texture, pH, and UV radiation. Proper mass production and application are essential for the biological control effectiveness of entomopathogenic nematodes (EPN). In addition, there is no problem in applying EPNs because they are simple to spray with common equipment and are compatible with almost all chemical fertilizers, but the compatibility is different from chemical pesticides.
... Abamectin was somewhat incompatible as it reduced the infectivity of S. braziliense and H. amazonensis but not H. bacteriophora or S. carpocapsae in this study. Koppenhöfer et al. [18] and Kary et al. [6] observed that S. feltiae was negatively affected by abamectin, while the effect on H. bacteriophora was very slight. Since the thickness of the epicuticle, cortical, and median cuticle layers of IJs differs between species [19], the different susceptibilities to abamectin between species may be due to differences in cuticles. ...
The spotted-wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is a pest that reduces the productivity of small fruits. Entomopathogenic nematodes (EPNs) and chemical insecticides can suppress this pest, but the compatibility of the two approaches together requires further examination. This laboratory study evaluated the compatibility of Steinernema brazilense IBCBn 06, S. carpocapsae IBCBn 02, Heterorhabditis amazonensis IBCBn 24, and H. bacteriophora HB with ten chemical insecticides registered for managing D. suzukii pupae. In the first study, most insecticides at the recommended rate did not reduce the viability (% of living infective juveniles (IJs)) of S. braziliense and both Heterorhabditis species. The viability of S. carpocapsae was lowered by exposure to spinetoram, malathion, abamectin, azadirachtin, deltamethrin, lambda-cyhalothrin, malathion, and spinetoram after 48 h. During infectivity bioassays, phosmet was compatible with all the EPNs, causing minimal changes in infectivity (% pupal mortality) and efficiency relative to EPN-only controls, whereas lambda-cyhalothrin generally reduced infectivity of EPNs on D. suzukii pupae the most, with a 53, 75, 57, and 13% reduction in infectivity efficiency among H. bacteriophora, H. amazonensis, S. carpocapsae, and S. brazilense, respectively. The second study compared pupal mortality caused by the two most compatible nematode species and five insecticides in various combinations. Both Heterorhabditis species caused 78–79% mortality among D. suzukii pupae when used alone, and were tested in combination with spinetoram, malathion, azadirachtin, phosmet, or novaluron at a one-quarter rate. Notably, H. bacteriophora caused 79% mortality on D. suzukii pupae when used alone, and 89% mortality when combined with spinetoram, showing an additive effect. Novaluron drastically reduced the number of progeny IJs when combined with H. amazonensis by 270 IJs and H. bacteriophora by 218. Any adult flies that emerged from EPN–insecticide-treated pupae had a shorter lifespan than from untreated pupae. The combined use of Heterorhabditis and compatible chemical insecticides was promising, except for novaluron.
... While spraying EPN formulation infective juvenile larvae of EPN can be passed through spray tubes with diameter of at least 500 μm, which is capable to withstand pressure up to 2000 kPa. 5 EPN infective juveniles (IJs) can also tolerate short-term exposure (2-24 hours.) to many agrochemicals, thus EPN can be tank-mixed and applied together. 20,21 Tank mixing of EPN-chemicals could offer a cost-effective alternative means to foliar integrated pest management (IPM) systems. As EPN's are very much sensitive to ultraviolet radiation, due to this reason EPN should better applied to above ground plant parts in the evening, early in the morning or in a cloudy weather, when the radiation is not so intense. ...
This study aimed to isolate native entomopathogenic nematodes (EPN) in the tea growing areas of Assam and to determine their potential for control of Termite and Cockchafer grub Soil samples were collected from three tea estates of jorhat, Assam for EPN isolation.A total of 30 soil samples were tested for the study. Larva of meal moth, Corcyra cephalonica was use as insect bait. Out of 30 samples 9 were found to be positive for EPNs. The infected host larvae were separated for extraction using “white trap method”. All the isolates were evaluated to ascertain their pathogenicity against Termite and cockchafer grub. From the experiment the isolated strain @ 50IJ, 75IJ and 100 IJ was found to be highly pathogenic to Termite and cockchafer grub, which recorded 94- 100% mortality in termite and 100% in all concentrations against cockchafer grub. After infection to prove the cause of mortality EPN could be recovered from the termite and cockchafer cadavers.
... As a result, these chemicals can frequently be tank mixed and applied with other pesticides. Some insecticides, including Imidacloprid [131], tefluthrin [132], neonicotinoid [133] and Bacillus thuringiensis [134] 10. ...
Chemical fertilizers and pesticides are presently accumulating in the environment harming the ecosystem, causing pollution, and spreading some of the diseases. Nematodes can be considered as entomopathogenic (EPN) if they fulfill criteria for entomo-pathogenicity when they bearing a pathogenic bacterium within a dauer juveniles juvenile, releasing the bacterium inside the host, actively seeking out and penetrating the host, rapid insect death, nematode and bacterial reproduction, reassociation of the pathogenic bacteria with new generations of dauer juveniles, and emergence of IJs from the cadaver so that the cycle can be repeated. Synthetic chemical pesticides have various disadvantages which include crop and soil contamination; killing of beneficial fauna and flora; resistance development in insects and adverse effects due to contamination in food chain; and other environment-related issues. To minimize pesticides contamination, EPN were identified as biological control agents and most suitable natural enemies of problematic insects because they reduce risk to humans and other related vertebrates.
... Synergistic or additive control effects of the combination of nematodes and insecticides on soil-inhabiting pests have been reported when compared with insecticides or nematodes alone (Koppenhöfer & Kaya, 1998;Koppenhöfer et al., 2000Koppenhöfer et al., , 2002Guo et al., 2016;Yan et al., 2019;Khan et al., 2021;Ozdemir et al., 2021). However, some insecticides with detrimental impact on the infectivity and survival of EPN have been observed (Rovesti et al., 1988;Rovesti & Deseö, 1990;Li et al., 1994;Yan et al., 2012;Kwizera & Susurluk, 2017). ...
Entomopathogenic nematodes (EPN) as an environmentally-friendly biocontrol agent in combination with low toxic insecticides can increase control efficacy against insect pests. In this study, Steinernema carpocapsae All (Sc-All) combined with four common insecticides was used to evaluate the control efficacy against chive root gnat (Bradysia odoriphaga), an important pest of vegetables, e.g., chive, onion or garlic. The compatibility of nematodes with insecticides and host-seeking behaviour were also evaluated by the laboratory bioassay. The results showed three insecticides (matrine, imidacloprid and chlorpyrifos) at the recommended concentrations (RC), 10% RC or 2% RC and insecticide phoxim at 10% RC or 2% RC had no effect on nematodes survival. Sc-All at 50 infective juveniles (IJ) per insect larva in the presence of the four insecticides at 10% RC demonstrated a potentiated, additive or a synergistic effect on the corrected mortality rates of insect up to 100% (imidacloprid) when compared with the corresponding insecticide and Sc-All alone. A synergistic effect resulting in lethal effect was found as early as at 24 h when 200 IJ of Sc-All per insect larva were combined with 10% RC imidacloprid, whilst only 9.4% and 0 corrected mortality were detected, respectively, when exposed to the same amount of imidacloprid and Sc-All alone. For the first time a Pluronic gel system assay revealed that the presence of insecticides significantly improved Sc-All host-seeking ability as early as 30 min post exposure. The results indicated that low doses of Sc-All-imidacloprid combination would be an effective strategy to control chive root gnat.
... Some characteristics make entomopathogenic nematodes (EPNs) promising for control of crop pests, such as the speed with which they attack the host, the ease of mass producing them at low cost and the wide spectrum of susceptible host pests (Georgis et al. 2006;Grewal et al. 2001). They also are compatible with many pesticides, allowing them even to be applied in combination with chemicals in some situations (Koppenhöfer et al. 2002;Negrisoli Jr. et al., 2008;Reis-Menini et al. 2008). Finally, they are able to seek out hosts that have cryptic habits (Kaya and Gaugler 1993) such as the root spittlebug. ...
... Similarly, Saffari et al. (2013) observed that T. tabaci prepupa was the most susceptible stage to EPN infection compared with second instar larva and Kashkouli et al. (2014) reported that prepupae and pupae of T. tabaci were more sensitive to EPN infection compared to larvae. One possible reason that prepupa are more susceptible is that this stage exhibits low mobility and thus eases the nematode attack (Koppenhofer et al., 2002). The pupal stage is also immobile but may not be as easy to penetrate as the prepupal stage. ...
Onion thrips Thrips tabaci Lindeman (Thysanoptera: Thripidae) is one of the most damaging insect pests of onion Allium cepa L., which is an economically important agriculture crop cultivated worldwide. This is first comprehensive study in which we have tested a broad range of entomopathogenic nematodes (EPN) species against different developmental stages of T. tabaci in laboratory, greenhouse and field trials. We performed several bioassays to assess the efficacy of different species of EPNs against different soil inhabiting stages of T. tabaci under various conditions. In screening bioassays, at 100 infective juveniles (IJs) cm⁻² mortality ranged from 8.5-74.2% and 5.0-62.7% among all the tested EPNs (Steinernema carpocapsae (ALL strain), S. glaseri (NC), S. riobrave (355), S. feltiae (SN strain), S. rarum (17 C&E), Heterorhabditis bacteriophora (VS), H. georgiana (Kesha), H. indica (HOM1), H. floridensis (K22) and H. megidis (UK211 strain)) in prepupae and pupae, respectively. Five EPNs species (H. bacteriophora, S. feltiae, S. carpocapsae, S. riobrave and H. indica) selected from the screening bioassay were further evaluated against prepupae, pupae and late second instar larvae at four different concentrations i.e. 50, 100, 150 and 200 IJs cm⁻². A clear dose response relationship was observed among all the tested species against all the developmental stages. The prepupal stage was the most susceptible (87.9% mortality) followed by pupae (78.1% mortality) and late second instar larvae (59.4% mortality) when exposed to H. bacteriophora at highest dose tested (200 IJs cm⁻²). Among the different temperatures tested, maximum efficacy was observed by all the tested EPNs at 25°C and 30°C followed by 35°C and 20°C with H. bacteriophora and S. feltiae being most virulent among all species at all the tested temperatures. In a potted soil bioassay, the lowest adult emergences were observed in the H. bacteriophora treatment for both prepupae and pupae. In potted plant bioassay under the greenhouse condition, significant lower number of adult emergence was observed among H. bacteriophora as compare to control group. Under field conditions, the lowest number of larvae (4.9 per plant in 2017-18 and 9.6 per plant in 2018-19) and adult (0.1 per plant in 2017-18 and 5.2 per plant in 2018-19) were observed in H. bacteriophora treated plots compared to control larvae (29.4 per plant in 2017-18 and 44.1 per plant in 2018-19) and adults (20.0 per plant in 2017-18 and 28.1 in 2018-19). Our results revealed that EPNs could be included in integrated pest management programs for T. tabaci in onion production systems.
... They are therefore recommended to counteract the outbreak of the species in Northern Italy in peach orchards. Further insecticide trials proved that these products are effective in killing the species in most of the commercial crops and nursery plants present in the study area (Marianelli et al., 2019;Mori et al., 2021;Santoiemma et al., 2021) and in other parts of the world (Koppenhöfer et al., 2002;Morales-Rodriguez & Peck, 2009;Pfeiffer, 2012). Nevertheless, given the non-negligible environmental impact and toxicological profile of these active ingredients, an integrated pest management approach based on biological control should be implemented in the near future. ...
Survival analysis is frequently used to assess the effectiveness of insecticide trials on insect survival. The target organism of this study is Popillia japonica, a pest currently causing considerable damage to various plant species in Northern Italy. Here, the effects of different insecticides, evaluated on insects by field trials in a peach orchard, were explored through non-parametric tests and semi-parametric marginal Cox proportional-hazard models. Adult insects were confined on peach plants in net cages containing 25 individuals each. Five insecticides (Abamectin, Acetamiprid, Deltamethrin, Phosmet and Sulfoxaflor) plus untreated control were tested with four net cages per treatment, following a completely randomized design. The non-parametric tests, performed both for right- and interval-censored data, and the marginal Cox model led to the same inferential conclusions. All the insecticides, in particular Abamectin, Acetamiprid, Deltamethrin and Phosmet, resulted to be effective in killing insects if compared to the untreated control.
... and Steinernema spp. (Stark 1996, Koppenhöfer et al. 2002, Alumai and Grewal 2004, Andaló et al. 2004, Meyer et al. 2012, Yan et al. 2012, Laznik and Trdan 2014, Chavan et al. 2018). These conflicting results confirmed the hypothesis that compatibility is not only species-specific but also strain-specific (Laznik et al. 2012). ...
The Mediterranean fruit fly Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae) is among the main pests of fruit crops worldwide. Biological control using entomopathogenic nematodes (EPNs) may be an alternative to suppress populations of this pest. Thus, the aim of this study was to evaluate the pathogenicity and virulence of six EPN isolates (Heterorhabditis bacteriophora HB, H. amazonensis IBCB-n24, Steinernema carpocapsae IBCB-n02, S. rarum PAM-25, S. glaseri IBCB-n47, and S. brazilense IBCB-n06) against C. capitata pupae. The compatibility of EPNs with different chemical insecticides that are registered for management of C. capitata was also assessed. Isolates of H. bacteriophora HB and S. brazilense IBCB-n06 at a concentration of 1,000 infective juveniles (IJ)/ml proved to be most pathogenic to C. capitata (70 and 80% mortality, respectively). In contrast, the isolates H. amazonensis IBCB-n24, Steinernema carpocapsae IBCB-n02, S. rarum PAM-25, S. glaseri IBCB-n47 provided pupal mortality of less than 60%. Bioassays to determine lethal concentrations indicated that concentrations of 600 IJ/ml (H. bacteriophora HB) and 1,000 IJ/ml (S. brazilense IBCB-n06) showed the highest virulence against C. capitata pupae. In contrast, the highest numbers of IJs emerged at concentrations of 1,200 and 200 IJ/ml. In compatibility bioassays, malathion, spinetoram, phosmet, acetamiprid, and novaluron were considered compatible with and harmless (Class 1) to H. bacteriophora HB and S. brazilense IBCB-n06, according to IOBC/WPRS. This information is important for implementing integrated management programs for C. capitata, using biological control with EPNs, whether alone or in combination with chemical insecticides.
... In combinations of EPNs with synthetic insecticide, the most consistent synergistic interaction was observed between the neonicotinoid imidacloprid and several EPN species (S. glaseri, H. bacteriophora, H. marelata, H. megidis) in third instars of several white grub species (e.g., Koppenhöfer et al., 2002). However, two rather scarab-specific species, S. kushidai and S. scarabaei, generally did not interact with imidacloprid. ...
The emphasis of this review is on the use and potential of entomopathogenic nematodes (EPNs) as biological control agents in sustainable food production across a wide range of agricultural and other commodities. To aid with the understanding of the potential of EPNs in sustainable food production, this review also provides overviews on EPN biology and ecology, mass production and application technology, and interactions with other management tools. First discovered in the 1920s, their commercialization as biopesticides in the 1980s was accompanied and followed by an exponential growth in research on their application, biology, and ecology, followed by a further expansion in more basic research areas since the mid-2000s. This review summarizes significant progress made in the research and application of EPN in insect pest management in important food crops including orchards, small fruit, maize, vegetables, tuber crops, greenhouses, and mushrooms. Significant factors affecting the success of EPN commercialization are also discussed. A growing interest in alternatives to synthetic insecticides and in organic agriculture opens opportunities for EPNs, but EPNs will need to be further improved with respect to efficacy, reduced costs, and ease of use. Moreover, their potential to recycle in host populations beckons to be further exploited for long term pest suppression.
... Similar way the botanical insecticides or chemical insecticides at recommended doses had no effect on nematode survival after 72 h of exposure as reported by Mohamoud and co-author [29] . In parallel to the results recorded in this study, imidachloprid showed no effect on mortality of H. bacteriophora [30] , H. indica [31] and S. carpocapsae [32] . Studies carried out by other authors also show low IJ mortality of S. carpocapsae when exposed to chlorpyrifos [28,33,34] . ...
The compatibility of entomopathogenic nematode Heterorhabditis indica with 14 insecticides, 6 fungicides and 7 herbicides commonly used in rice ecosystems was investigated under laboratory conditions. The effect of these chemicals on nematode viability and virulence upon direct exposure to chemicals at recommended concentrations was studied. H. indica was tolerant to most of the insecticides tested with less than 10% nematode mortality observed in all insecticides except monocrotophos (19.5%) and cartap hydrochloride (100%) after 72 h of exposure. Less than 10% mortality was observed in all fungicides tested except tricyclazole (14.5%) and carbendazium +mancozeb (21.5%) after 72 h of exposure to fungicides. Nematode mortality in case of herbicides ranged from 3.5% to 18% after 72 h of exposure. Insecticides showed only a marginal effect on the virulence of H. indica. Mortality of Galleria mellonella larvae in all the treatments was more than 90% except in treatments with chlorpyrifos (80%) and monocrotophos (60%) treated infective juveniles after 48 h. These results show that H. indica is compatible with all the tested agrochemicals except monocrotophos and cartap hydrochloride among insecticides, tricyclazole and carbendazium+mancozeb among fungicides, and pendimethalin among herbicides.
... According to the results of this study, imidacloprid and cyflumetofen showed no adverse effect on the survival, infectivity, and reproduction rates of both isolates and can be considered as the most compatible pesticides. In this sense, our results support the studies in which were reported that both S. feltiae and H. bacteriophora are compatible with imidacloprid (Koppenhöfer et al. 2002;Koppenhöfer and Fuzy 2008;Laznik and Trdan 2014;Yan et al. 2012). Since imidacloprid is registered for drip irrigation and natural habitat of EPNs is soil, combine usage of them might provide long-lasting pest management over soil-dwelling insects. ...
Compatibility of the Turkish entomopathogenic nematode isolates Steinernema feltiae (Filipjev) and Heterorhabditis bacteriophora (Poinar) with six chemical pesticides registered for vegetable crops in Turkey was investigated. Mortality, infectivity, and reproduction capacity of pesticide-treated EPNs have been assessed. Our study indicated that imidacloprid and cyflumetofen showed no adverse effect on the survival, infectivity, and reproduction rates of EPNs and can be considered as the most compatible pesticides. The fungicides, fluxapyroxad + difenoconazole and ametoctradin + dimethomorph, caused significantly higher mortality on S. feltiae; however, only fluxapyroxad + difenoconazole showed the negative effect on the survival of H. bacteriophora. Although spiromesifen, spinosad and fluxapyroxad + difenoconazole treated H. bacteriophora had significantly lower reproduction capacity, no negative effect has been observed on the progeny production of S. feltiae among the tested pesticides. In this study, compatibility of cyflumetofen, fluxapyroxad + difenoconazole and ametoctradin + dimethomorph with EPNs have been reported for the first time. The results of the present study will contribute to cost-effective and sustainable management of vegetable pests.
... Popillia japonica Sg 5X10 9 /ha 44-66 [119] Popillia japonica Hb 2.5X10 9 /ha 34-98 -Cyclocephala borealis Hb 2.5X10 9 /ha 47-83 [120] Popillia japonica Hb, Sg with Neonicotinoides -75 [121] Golfcourse Scapteriscus spp. Sc 2X10 5 /m 2 100 [122] Phylloperta horticola Hb 0.5-1.5X10 ...
A piece of brief information on EPNs
... EPNs can also be integrated with other pest management tactics since they can be applied in standard spray equipment and are compatible with many agrochemicals (Koppenhöfer and Grewal, 2005). EPNs are reported to have a synergistic relationship with certain chemical pesticides (Koppenhöfer et al., 2002). Arthurs et al. (2004) emphasized the potential of EPNs to be used against different foliar and wood boring insect pests. ...
Wireworms, the larval stage of click beetles (Coleoptera: Elateridae), are economically important soil-dwelling pests that attack many field crops worldwide. Wireworms have become a serious threat to spring wheat in the Northern Great Plains because of lack of effective control measures, creating a need for alternative control methods such as biological control with entomopathogenic nematodes (EPNs). A laboratory bioassay was used to test ten EPN strains and identify infective EPN strains against the sugarbeet wireworm, Limonius californicus (Mannerheim) (Coleoptera: Elateridae). Steinernema carpocapsae (Weiser) (All and Cxrd strains) and S. riobrave Cabanillas, Poinar, and Raulston (355 and 7–12 strains) killed 60–70% of L. californicus larvae in four weeks when applied at 700 Infective juveniles (IJs) (25 IJs/cm²), 1400 IJs (50 IJs/cm²), 2800 IJs (100 IJs/cm²), and 5600 IJs (200 IJs/cm²) per larva in the laboratory. Also, Heterorhabditis bacteriophora (Poinar) VS strain and Steinernema rarum (Doucet) 17c + e strain caused 50–60% mortality to L. californicus larvae after four weeks when applied at 5600 IJs/larva. However, regardless of the concentration applied, the penetration rate of infective juveniles into the host did not exceed 33%. In shade house trials, S. riobrave and S. carpocapsae strains caused 34–56% L. californicus mortality after four weeks with 50 and 56% mortality caused by S. carpocapsae All and S. riobrave 355 strain, respectively when applied at the rate of 80,000 IJs/pot. These results suggest that S. carpocapsae and S. riobrave may have significant potential for protecting spring wheat crops from L. californicus.
... The above result differs from the findings of LeBeck et al. (1993) that EPNs are most efficient of all against all the pre-imaginal stages of insects, as they can then enter the latter's bodies with relative ease. The above can be explained by means of the low mobility of the pupal stages, which facilitates the attachment of nematodes to them (Koppenhofer et al. 2003). An experiment conducted by Trdan et al. (2007) on banded greenhouse thrips showed that the soil-dwelling life stages are more sensitive to EPNs than are the adults. ...
... IJs can pass through the spray tubes with diameters of at least 500 μm and are capable of withstanding pressures up to 2 000 kPa (Wright et al. 2005). Furthermore, IJs can tolerate short-term exposure (2-24 h) to many chemical and biological insecticides, fungicides, herbicides, fertilisers, and growth regulators and can be tank-mixed and applied together with such products (Head et al. 2000;Koppenhöfer et al. 2002;Krishnayya & Grewal 2002;De Nardo & Grewal 2003;Schroer et al. 2005;Laznik & Trdan 2014). Nematode-pesticide combinations in tank mixes could offer a cost-effective alternative to foliar integrated pest management (IPM) systems. ...
Plants under herbivore attack emit mixtures of volatiles that can attract the natural enemies of the herbivores. Entomopathogenic nematodes (EPNs) are organisms that can be used in the biological control of insect pests. Recent studies have shown that the movement of EPNs is associated with the detection of chemical stimuli from the environment. To date, several compounds that are responsible for the mediation in below ground multitrophic interactions have been identified. In the review, we discuss the use of EPNs in agriculture, the role of belowground volatiles and their use in plant protection programmes.
... Heterorhabditis amazonensis was considered compatible with the three insecticides Actara®, Warrant®, and Premio® used on tomato. Various works on compatibility show that insecticides with the active principle based on thiametoxam, imidacloprid, and chlorantraniliprole did not present a negative effect on the viability and infectivity of the EPN, so these can be used together in pest control (Koppenhöfer et al 2002, Koppenhöfer & Fuzy 2008, Sabino et al 2014. All tested products were considered non-toxic to EPNs. ...
The present research aimed to investigate the compatibility of entomopathogenic nematodes (EPNs) and registered insecticides for the control of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in the tomato crop, as well as the susceptibility of pupae of T. absoluta to EPNs combined with different percentages below the recommended dose of compatible chemical insecticides in laboratory conditions and in the greenhouse. The species of EPN used was Heterorhabditis amazonensis JPM4. The insecticides used were Actara®, Premio®, and Warrant®. In the compatibility test between the EPNs and insecticides, the viability and infectivity of the nematodes after contact with the insecticides were evaluated. An assessment of the efficacy of the combined application of different doses of the insecticides and the EPNs on T. absoluta was carried out in the laboratory and greenhouse. The efficacy of the combined application of the insecticides and the EPNs on T. absoluta via soil was carried out at application intervals of 1 and 2 weeks. The EPNs were compatible with the three insecticides tested. In the laboratory, there was an additive effect of the combined application of insecticides and H. amazonensis as the dose of the products increased. In the greenhouse assay, the combined application of EPNs and insecticides induced mortality above 48%, and the combined application of EPNs and Warrant® 75% presented 60% of mortality. The weekly and fortnightly applications were effective in controlling T. absoluta, and there was no difference between the insecticides tested when applied together with the nematodes.
... These stressors could be insecticides or may be pathogens or xenobiotics. Insecticides are designed to achieve high mortality of target organisms and could be combined with microbial control agents to mitigate insecticide resistance or to increase efficacy (Agnew et al. 2004;Alizadeh et al. 2007;Aufauvre et al. 2012;Farenhorst et al. 2009;Koppenhöfer et al. 2002). This study was designed to gather information regarding exposure of houseflies to an entomopathogenic fungus (B. ...
Insecticide resistance in the housefly Musca domestica is hampering pest management. However, entomopathogens, possibly in combination with insecticides, may have control potential against resistant houseflies. This study investigates the combination of the entomopathogenic fungus Beauveria bassiana and the neonicotinoid insecticide, imidacloprid against a susceptible and a resistant housefly strain, respectively under laboratory conditions. The fungus and insecticide were tested alone and in combinations at LC30. Significant and synergistic interactions between B. bassiana and imidacloprid were observed with increased mortality rates of the combined treatment as compared to individual treatment in housefly strains 772a (susceptible) and 766b (resistant). Significant differences in the GST and P450 activities for both strains were found. Female 766b flies caused 15- to 237-fold increases in gene expression of xenobiotic response genes for B. bassiana and 23- to 120-fold changes for imidacloprid. The combination of B. bassiana and imidacloprid caused significant synergistic interaction when applied against two housefly strains irrespective of order of application. The effect was highest when the insecticide was applied first. The resistant housefly strain had elevated detoxification enzymes and higher expression of detoxification genes, but showed the same level of susceptibility to the combined fungus/insecticide treatment as the susceptible strain.
... However, when nematodes were inoculated during the late larval instar of M. rufiventris, both nematodes and wasps reproduced in the same host and resulted in greater overall mortality on S. littoralis larvae than either agent inflicted alone. Before embarking on a combined application program, the nature of interactions (antagonistic, additive, or synergistic) between two tactics should be elucidated (Koppenhöfer and Fuzy, 2002). ...
Entomopathogenic nematodes (EPNs) have been demonstrated to be effective against a diverse number of tomato pests, especially against soil-dwelling pests or those in cryptic habitats such as inside galleries of plants. The ability of EPNs to seek out and kill insects in these habitats, where chemical insecticides fail, makes these biocontrol agents especially attractive. Their efficacy and compatibility with other biocontrol agents and with agrochemical products promote their incorporation in integrated pest management strategies on tomato crops. The use of EPNs against aboveground tomato pests requires improved application and formulation technology, and appropriate EPN species to withstand the adverse climatic conditions exposed to the crop foliage (high temperature, low moisture, and exposure to sunlight). End-user education and marketing support for the use of entomopathogenic nematode products is needed to expand the use of these in tomato pest management systems.
... Combinations of H. bacteriophora and the anthranilic diamide chloranlraniliprole resulted in mostly synergistic but also additive mortality of third-instar Anomala orientalis, Popillia japonica, and Cyclocephala borea lis in greenhouse and field experiments (Koppenhöfer and Fuzy, 2008). Imidacloprid mostly interacted synergistically in combinations with several EPN species (S. glaseri, H. bacteriophora, H. marelata, H. megidis) in third instars of Cyclocephala borealis, C. hirta, Cyclocephala pasadenae, P. japonica, and A. orientalis (Koppenhöfer et al., 2000(Koppenhöfer et al., , 2002Koppenhöfer and Fuzy, 2008). The EPN-imidacloprid interaction is pri marily based on reduced defensive and evasive larval behaviors resulting in increased host attachment and penetration (Koppenhöfer et al., 2000). ...
This chapter focuses on the principal and most studied abiotic factors (temperature, moisture, UV, chemical inputs). It provides an updated overview of what has been learned regarding abiotic effects on different entomopathogen groups during the past 30 years. It focuses on entomopathogens that have emonstrated potential roles in microbial control. Abiotic environmental factors have diverse effects on entomopathogen survival, efficacy, and dispersal in the ecosystem. Extreme temperatures, desiccation, and UV radiation have the most detrimental effects on pathogen survival despite the existence of durable resting stages for most groups. Few field studies have investigated the influence of temperature on the severity and rate of transmission of viral disease. Since low temperatures do not affect the lethality of most baculoviruses, these viruses could be applied for area-wide management to reduce pest populations early or before the start of the growing season, as demonstrated against Helicoverpa zea and Heliothis virescens.
... EPNs are soil-dwelling parasites of insects, and they occur widely in natural and agricultural ecosystems across the world. They have been widely accepted as potential biocontrol agents of the larval stages of white grubs 3 . The genera Heterorhabditis (family: Heterorhabditidae Poinar 1976) and Steinernema (family: Steinernematidae Chitwood and Chitwood, 1937) have generated much interest as poten- tial biocontrol agents as they carry the lethal symbiotic bacteria Photorhabdus and Xenorhabdus respectively, in their guts. ...
Over the past 10 years, farmers of Uttaranchal and western Uttar Pradesh, India have been fighting a losing battle against the white grub (Coleoptera: Scarabaeidae) infestation of sugarcane crop. Pesticides have failed to address the problem as evident from the observed infestation levels of 10-24 grubs/m². During 2008-2014, the Division of Nematology, Indian Agricultural Research Institute, New Delhi launched a biocontrol project involving treatment of the white grub-afflicted fields with entomopathogenic nematodes (EPNs)-infected Galleria mellonella cadavers. This initiative, spread over the districts of Ghaziabad, Meerut, Amroha, Saharanpur, Gajraula, Bulandshahar and Hapur, was undertaken in collaboration with a non-governmental organization - the Foundation for Resources Management and Environmental Remediation - and local sugar mills, and by enlisting the active participation of the farming community. It was perceived that this technology had a greater possibility of evolving into a long-term, sustainable biocontrol strategy if the EPNinfected Galleria were sourced in each village. Capacity-building programmes were undertaken in the villages with special focus on empowering women, and small and marginalized farmers by educating them on rearing and infecting Galleria. This initiative has resulted in an average reduction of 69.1% in the white grub population and an average increase of 60.49 q/acre in sugarcane yield over untreated control.
... IJs can tolerate short-term exposure (2-24 hours) to many chemical and biological insecticides, fungicides, herbicides, fertilizers, and growth regulators and can thus be tank-mixed and applied together [78,79,80,81]. Nematode-chemical combinations in tank-mixes could offer a cost-effective alternative to foliar integrated pest management (IPM) systems. ...
... The arcsine transformed percentage data and the fresh yield of peanut from each treatment were analyzed by one-way ANOVA, followed by Tukey's multiple means comparison procedure at P ¼ 0.05 (SPSS 16.0, SPSS Inc., Chicago, IL). Synergistic, additive, or antagonistic interactions between agents in the combination treatments were determined using a v 2 test with the control corrected data (Finney 1964, McVay et al. 1977, Koppenhö fer et al. 2002, Koppenhö fer and Fuzy 2008b. The expected additive proportional mortality M E for the combinations of EPN-insecticide was calculated by M E ¼ M N þ M I (1 ÀM N ), in which M N and M I were the observed proportional mortalities caused by nematodes and insecticide alone, respectively. ...
Combinations of entomopathogenic nematodes Steinernema longicaudum X-7 and Heterorhabditis bacteriophora H06 with chlorantraniliprole, diflubenzuron, and imidacloprid insecticides at different rates for the control of the white grub, Holotrichia oblita Faldermann (Coleoptera: Scarabaeidae), were evaluated both in the laboratory and in peanut fields. In the laboratory, the combinations had a synergistic or additive effect on the second-instar larvae of H. oblita and caused faster mortality than one nematode species or insecticide alone. Heterorhabditis bacteriophora-chlorantraniliprole and H. bacteriophora-imidacloprid showed synergistic effects on the larvae. When higher concentrations of the insecticides were combined with nematodes, the stronger synergistic effects were found. In peanut fields, S. longicaudum-imidacloprid, H. bacteriophora-imidacloprid, or H. bacteriophora-chlorantraniliprole also showed synergistic effects against the larvae. The three nematode-insecticide combinations produced similar percentage reductions of the grub larvae and less percentages of injured legumes, compared with the chlorpyrifos treatment. Cost-benefit analysis showed that H. bacteriophora 5.0 × 10(3) infective juveniles (IJs) per plant (equal to 7.5 × 10(8) IJ ha(-1)) combined with imidacloprid at the recommended concentration is a practical strategy for the practitioner to manage the white grubs in the peanut production.
Many organisms, including beneficial entomopathogenic nematodes (EPNs), are commonly found in the soil environment. EPNs are used as biopesticides for pest control. They have many positive characteristics and are able to survive at sites of application for a long time, producing new generations of individuals. The occurrence of populations depends on many environmental parameters, such as temperature, moisture, soil texture, and pH. Extreme temperatures result in a decrease in the survival rate and infectivity of EPNs. Both high humidity and acidic soil pH reduce populations and disrupt the biological activity of EPNs. Nematodes are also exposed to anthropogenic agents, such as heavy metals, oil, gasoline, and even essential oils. These limit their ability to move in the soil, thereby reducing their chances of successfully finding a host. Commonly used fertilizers and chemical pesticides are also a challenge. They reduce the pathogenicity of EPNs and negatively affect their reproduction, which reduces the population size. Biotic factors also influence nematode biology. Fungi and competition limit the reproduction and survival of EPNs in the soil. Host availability enables survival and affects infectivity. Knowledge of the influence of environmental factors on the biology of EPNs will allow more effective use of the insecticidal capacity of these organisms.
Entomopathogenic nematodes (EPNs) play a crucial role in biological control, but they can be also applied together with pesticides. Therefore, the compatibility of pesticides with EPNs and the influence on their behavior significantly affect field success. This study investigated how selected pesticides (Deltamethrin, Imidacloprid, Pendimethalin, 2,4-D, and Boscalid + Pyraclostrobin) affect the orientation behavior of three commercial EPN species. Trials were conducted using steel olfactometers followed by the assessment of EPN dispersal ratios after 24 hours. The study was conducted in the Laboratory of the Plant Protection Department, Faculty of Agriculture and Natural Sciences, Bilecik Şeyh Edebali University between 2022 and 2023. According to the results, while nearly all pesticides exhibited a significant impact on the dispersal behavior of EPNs, the most notable effects were observed in the trials involving 2,4-D and Imidacloprid. These two pesticides demonstrated both repellent and attractive effects on different EPN species. The impact of other pesticides was comparatively negligible. All EPN species exhibited higher orientation towards larvae than the control application. The orientation behavior displayed variations depending on the pesticide type and the EPN species involved. It is expected that this study will contribute to our understanding of the relationship between EPNs and pesticides, and ultimately enhancing the efficacy of EPNs.
Root-feeding white grubs are one of the most serious pests of honeysuckle trees ( Lonicera japonica ) in China, directly damaging their roots and facilitating infection by soil pathogens. Entomopathogenic nematodes (EPNs) are considered as potential control agents against soil-dwelling insect pests. This study aimed to identify effective EPN species against white grubs through bioassay and field experiments. Among the EPN species screened against Holotrichia oblita under laboratory conditions, Steinernema feltiae and Heterorhabditis indica had low virulence, while S . longicaudum, S . glaseri , and H . bacteriophora applied at a rate of 400 IJs/larva caused a higher corrected mortality (80.00 ± 5.77%), which screened them as good candidates for future applications. The field experiments showed that both S . longicaudum and H . bacteriophora were approximately as effective in reducing white grubs as the insecticide phoxim, whereas S. glaseri caused a significantly lower reduction compared with these two EPNs and phoxim. Plant mortalities obtained from S . longicaudum, H . bacteriophora and the insecticide treatment plots were significantly lower than those observed in the water-treated control plots. All EPNs examined could establish well in the treated honeysuckle fields for 42 d, confirmed by Tenebrio molitar larvae baiting technique. Our findings suggest that EPNs could provide curative efficacy against white grubs and significantly reduce plant death in honeysuckle fields.
Entomopathogenic nematodes (EPNs) are environmentally friendly, safe and effective biocontrol agents for a variety of insect pests that harm agricultural and horticultural crops. They have been reported from all over the world and mass-produced for utilization against insect pests. When used in conjunction with pesticides, these EPNs have shown better outcomes. The growing interest in organic agriculture as an alternative to synthetic pesticides creates prospects for the integrated use of EPNs and insecticides in agricultural pest management. However, EPNs first need to be enhanced in terms of efficacy, cost savings, and convenience of use. Furthermore, their ability to recycle in the host and their tolerance to various chemical pesticides used in agriculture needs to be explored for
long-term pest control. This chapter summarizes significant progress made in the research and application of EPNs in combination with chemical pesticides for insect pest management programs.
Dealing with different biocontrol agents for the management of plant parasitic nematodes
Entomopathogenic nematodes (EPN) are found in all inhabited continents except Antarctica (no report yet) and a range of ecologically diverse habitats, from cultivated fields to deserts. Steinernema and Heterorhabditis are the well studied genera which belong to the family Steinernematidae and Heterorhabditidae, associated with symbiotic bacteria Xenorhabdus and Photorhabdus respectively. As far as entomopathogenicity is concerned genus Oscheius is less studied, also having ability to kill the host insect due to the mutually associated with efficacious bacterial genera of Pseudomonas, Enterococcus and Serratia. The bacterial complex of these nematodes makes them a prominent mediator for the bio-management of many insect pests. Many studies have proven the active and main involvement of nematode’s bacterial partner by releasing secondary metabolites in causing septicemia and oenocytoids. Globally, both the genera, that is, Steinernema and Heterorhabditis, are represented by 100 and 16 species, respectively, while Oscheius is represented by 45 species, out of which 17 are from the Indian subcontinent. The information on EPN diversity is limited in India. EPN show high potential for plant protection and can play a major role in Integrated Pest Management (IPM) of insects.
The subterranean insect Bradysia cellarum Frey (Diptera: Sciaridae) is a notorious and major pest of Chinese chives, Allium tuberosum Rottler ex Sprengle (Amaryllidaceae) in China. Current chemical control of B. cellarum results in low insecticide efficacy, high cost and pesticide resistance, therefore there is an urgent need for sustainable management. Here, greenhouse experiments were conducted to evaluate the potential biocontrol agent Stratiolaelaps scimitus Womersley (Acari: Laelapidae) against B. cellarum. The number of B. cellarum larvae in soil declined from 17.6 to 0 in 4 months after releasing predatory mites in high density (5,000 adults per row); treatment was less effective under low densities of 2500 adults per row. To determine whether S. scimitus can be used in combination with soil solarization by film mulching over 40 °C for 4 h, we also evaluated heat tolerance of S. scimitus in laboratory and its control efficacy against B. cellarum after high-temperature treatment mimicking the film mulching in greenhouse. As our results showed that egg hatchability of S. scimitus was 2.6% at 38 °C and adult survival rate was 2% at 40 °C for 4 h, respectively, we concluded S. scimitus was largely inviable and could not reproduce at 40 °C. This temperature was the baseline of soil solarization, suggesting predatory mites should be released after soil solarization. When using S. scimitus after soil solarization or when using soil solarization as single treatment, fly larvae declined similarly from initial density of 18 to 0 or 17.2 to 0, respectively, within a month. Thus, our study suggests the potential of S. scimitus as a biocontrol agent of B. cellarum in greenhouse, and the most effective strategy is to combine film mulching and predatory mites (after soil heating) to control B. cellarum in chive productions.
The world population growing very fast and this leads to food scarcity. For the survival enormous amount of food is required. To fulfill the daily requirements of the population huge amount of food is required. Most of the world's population depends on agricultural practices for yielding food. For this purpose, various agrochemicals apply to the crops. These agrochemicals are plants stimulators, herbicides, insecticides, weedicides, molluscicides, and rodenticides. These agrochemicals prevent the plant's enemies and enhance crop production. But excessive use of agrochemicals on crops leads to soil contamination, air contamination, and water contamination. Mainly soil contaminated by these agrochemicals and disturb the soil environment. Agrochemicals impose a negative impact on the soil of living animals. In agrochemicals, heavy metals are present and they disturb the physiology of animals. Here we suggest some remediation to minimize the negative impact of agrochemicals on soil environments and soil living things. Vermiremediation, phytoremediation, and remediation via nematodes. These techniques are very helpful for the minimization of negative impacts on soil environments. Abstract JPS Scientific Publications, India Agrochemicals, Soil fertility, Isolation technique, Heavy metals, Remediation.. Uttarakhand.
The present book entitled “Biodiversity: Status Threats and its Conservation Strategies” gathers the recent and latest innovative research in the area of Biodiversity Status their Threats and its Conservation programs. The book is the most wide-ranging and convincing account available to analyze the multidisciplinary and multifaceted nature of innovations in the field of Biodiversity conservation. Each and every chapter contains a comprehensive explanation of the projected topics with well explained appropriate tables and photo plates This book composing of 12 highly selective chapters from 28 authors will present their many facets innovations in the context of Current status, various threats to biodiversity, and its conservations strategies. The breadth of this work will allow the readers to gain a complete and panoramic view and can be used as a reference
source for various topics in the conservation of Biodiversity.
The potato tuber moth (PTM) Phthorimaea operculella (Zeller, 1873) is a major pest of Solanaceae crops globally. PTM is mainly controlled using chemical pesticides. The objectives of this study were to compare the efficacy of two species of entomopathogenic nematode (EPNs), Heterorhabditis bacteriophora Poinar, 1976 and Steinernema feltiae (Filipjev, 1934) Wouts, Mracek, Gerdin & Bedding, 1982, against PTM pre-pupa and pupa, while also assessing their interaction in combination with abamectin in a series of laboratory and greenhouse assays. The results showed that S. feltiae was considerably more virulent than H. bacteriophora against both PTM life stages tested. PTM pupae were less susceptible to EPN than pre-pupae: LC50 values for pupae were 721 and 570 IJs/insect for H. bacteriophora and S. feltiae, respectively; corresponding values for pre-pupae were 98 and 6 IJs/insect, respectively. While both species of EPN were negatively affected by abamectin, the effect on H. bacteriophora was less pronounced. This present study shows that the extent to which the nematodes interact with chemical pesticides is dependent on a number of factors, including nematode species, concentration of combined agents, developmental stage of the targeted pest, exposure method and the complexity of the environment in which the interaction takes place. In the glasshouse study, for S. feltiae, synergistic effects were observed only in the combinations which included lower rates of abamectin and higher S. feltiae concentrations. In the case of H. bacteriophora, other than at the lower concentrations of both the insecticide and the nematode (where the interaction was additive), all other combinations were synergistic. That there were more synergistic interactions in the H. bacteriophora + insecticide combinations is most likely attributable to the lower susceptibility of H. bacteriophora to abamectin compared to S. feltiae. This study demonstrates that combined applications of chemical insecticides and entomopathogenic nematodes allow for a reduction of both inputs. For end users, reducing nematode and abamectin inputs make their combined use an extremely attractive proposition, in both economic terms and as a resistance management strategy.
This study aimed to evaluate the combination effect of Heterorhabditis bacteriophora HP88 and H. indica LPP1, with the acaricides deltamethrin, amitraz and chlorfenvinphos, and the essential oil (EO) of Lippia triplinervis, against engorged females of Rhipicephalus microplus. In order to verify the effect of acaricides and EO, the adult immersion test was used, and in the groups treated only with entomopathogenic nematodes (EPNs), 150 infective juveniles were used per female. In the treatments with nematodes in combination with the acaricides or EO, the females were immersed in the solutions (acaricide or EO) and then transferred to Petri dishes for application of the nematodes. The treatment with acaricides resulted in a control percentage lower than 70%, except in the group treated with chlorfenvinphos in the second experiment (84.3%). The control percentage was 73% for L. triplinervis EO, and greater than 90% in all the groups treated with nematodes. For treatments with EPNs combined with the acaricides or EO, the efficacy was greater than 95% (except for deltamethrin + HP88), and reached 100% in the treatment with LPP1 + amitraz. It can be concluded that the EPNs at the concentrations tested were compatible with the acaricides deltamethrin, amitraz and chlorfenvinphos, and with the EO of L. triplinervis. These combinations enhance the effect of these control agents.
Apis mellifera est un insecte pollinisateur jouant un rôle économique et écologique majeur. Depuis plus d’une vingtaine d’années, d’importantes pertes de colonies d’abeilles ont été recensées à l’échelle mondiale. L’origine de ce phénomène impliquerait de nombreux facteurs de stress qui pourraient en outre interagir entre eux. Ce travail de thèse a eu pour but d’évaluer l’impact sur la santé de l’abeille de l’association entre un facteur biotique, le parasite microsporidien Nosema ceranae, et un facteur abiotique, des insecticides neurotoxiques à faibles doses. Des études en laboratoire ont montré que l’association N. ceranae-insecticide entraine une surmortalité significative, et plus précisément un effet synergique sur la mortalité des abeilles. Cet effet synergique semble indépendant de l’ordre d’exposition des abeilles aux deux facteurs de stress. De plus, lorsqu’ils ont été appliqués dès l’émergence des abeilles, ces facteurs ont eu un impact plus fort sur la mortalité. La réponse de l’abeille à N. ceranae et aux insecticides a ensuite été analysée à l’échelle transcriptomique. L’analyse du transcriptome de l’intestin a été réalisée en combinant une approche globale de séquençage à haut débit (RNA-Seq) et un suivi de l’expression d’une sélection de gènes par qRT-PCR. L’exposition à N. ceranae et aux insecticides a entraîné des modifications de l’expression de gènes impliqués dans les défenses de l’abeille (immunité, détoxication) et dans les métabolismes du tréhalose et de la chitine. De nombreuses perspectives à ce travail sont envisageables dans le but de mieux appréhender la réponse de l’abeille à différents facteurs de stress, notamment en combinant des expérimentations en laboratoire avec des études de terrain.
Entomopathogenic nematodes have shown potential as biocontrol agents targeting larvae of the annual bluegrass weevil, Listronotus maculicollis Kirby, a major golf course turf pest in eastern North America with widespread insecticide resistance. Control levels of single applications of nematodes have been too low and variable in the past to support application by golf course managers for weevil control. We examined if splitting nematode applications in two at half rates approximately 1 week apart as well as combinations of the nematodes with the neonicotinoid imidacloprid could improve nematode performance. In greenhouse experiments in pots with grass infested with ABW larvae, the entomopathogenic nematodes Steinernema carpocapsae, S. feltiae, and Heterorhabditis bacteriophora were similarly effective for larval control. Combination with imidacloprid resulted in additive weevil mortality. In a field experiment with natural infestations of larvae using 1.25 and 2.5 × 10⁹ nematodes ha⁻¹, respectively, of S. carpocapsae and H. bacteriophora, additive mortality in the combinations with imidacloprid amounted to 82% and 79% control, respectively, at the high nematode rate. In three additional field experiments using only S. carpocapsae, the low and high nematode rate provided on average 59% and 74% control, respectively, while their combinations with imidacloprid provided 75% and 84% control, respectively. Imidacloprid alone averaged 37% control. Mortality in all combination treatments was additive. Splitting S. carpocapsae applications provided a marginal increase in mortality that was significant only in one of three experiments. However, combining split applications with imidacloprid provided 88–95% control which could offer an effective alternative to synthetic insecticides.
Microbial insecticides or entomopathogens are effective and eco-friendly insect pest management options. But slow mode of action and lack of a visual pest control, as expected by a farmer, mostly limits their wide commercial usage. The present day regular and high incidences of insect pests, due to intensive monocultures, warrant inevitable use of high doses of chemical pesticides. However, their judicious application depends on the diverse environmental threats associated. So, deployment of both entomopathogenic microbes and chemical pesticides together is considered to reduce the risk to the environment. Various studies also reported more efficient synergistic interactions in combined use than for independent applications. Synergism has the ability to reduce the pesticide doses. Most importantly, the combined application due to synergism can effectively tackles the pest problem and also helps in establishment of an entomopathogen in a given ecosystem. Once established, the entomopathogens can effectively manage the pest population build up in an eco-friendly manner, and over the years they can evade the use of pesticides or, if not so, reduce their dosage. The present chapter critically discusses possible synergism between entomopathogens and chemical pesticides and the present status of pest management achieved through this approach, in the context of latest research findings.
The use of synthetic insecticides and biological agents are the main tools to control agricultural pests, each with its own advantages and disadvantages. Although the use of chemical compounds is inevitable in some cases, attitudes of consumers and agricultural experts towards healthy products and lower environmental contamination have increased the prevalence and preference for biological agents. Among them, insect pathogens have been considered as the unique and widely distributed components in many ecosystems, due to their diverse virulent mechanisms. The entomopathogenic fungi (EF) and nematodes have been commercialized as biologically active insecticides against a wide range of pests. Although many environmental benefits for these compounds have been identified, the disadvantages such as low virulence due to behavior or habitat of target pest, delayed killing performance and sensitivity to environmental factors, lead to simultaneous use of entomopathogens with one or more chemical insecticides in reduced doses. In this review, the possibility of simultaneous use of chemical insecticides from different classes with EF and nematodes were discussed by indicating severally up-to-date studies. The effects of insecticides on cessation or induction of germination and conidiation of fungi have been reported, depending on the concentrations of used chemicals. Field or laboratory experiments have shown synergism or antagonism of EF with some insecticides. In case of entomopathogenic nematodes, the effects of insecticides from different classes have been investigated on mobility and survival of nematodes, as well as on synergistic or additive effects. Generally, the possibility of simultaneous use of chemical insecticides with these two groups of entomopathogens depends on target pest, spraying method, insecticide class or formulation and origin of entomopathogens.
2018. Nicienie entomopatogenne w lasach i szkółkach leśnych. Sylwan 162 (xx): x−y. There are many serious pests in forest nurseries, which can be killed by entomopathogenic nematodes (EPNs) applied to soil. The paper presents a method of biological control, which is appropriate for destroying harmful insects, and is an alternative to chemicals−based approach. Both, the rules and technical conditions concerning the application of biological preparations for insects control are discussed. Facing the problem of excessive chemicalization, especially in the forest nurseries, the authors, in accordance with EU Directives, reviewed the opportunities for biological methods of forest crops protection against seven of the most harmful species of insects. Selection of EPNs for control of a particular pest insect is based on several factors that include the nematode's host range, host finding or foraging strategy, tolerance of environmental factors and their effects on survival and efficacy (temperature, moisture, soil type, exposure to ultraviolet light, salinity). The most critical factors are moisture, temperature, pathogenicity for the targeted insect, and foraging strategy. Entomopathogenic Nematodes for Control of Insect Pests from the genera Steinernematidae and Heterorhabditidae cooperating with mutualistic bacteria were described accurately in this paper. They are capable of killing a broad range of insects. Applied to the soil, they can persist long in the environment and moreover they improve the soil quality. However, along with all the benefits, disadvantages of presented method were also discussed. Namely the abiotic conditions, technique, and limitations of their effectiveness. We presented a list of commercially produced EPNs, which are currently in use in Poland. We also reviewed the World's literature on the successful use of EPNs and discussed aspects of their commercialization. The wider use of biological preparations containing EPNs should be implemented in the near future. ABSTRACT Nicienie entomopatogenne w lasach i szkółkach leśnych 2018085 ver_01 Wstęp Poziom świadomości społeczeństwa związany ze stopniem zanieczyszczenia środowiska, szkod− liwością pestycydów oraz wzrostem cen, kosztów i nakładów ich stosowania coraz mocniej sty−
This book contains chapters that capture the full breadth of the basic and applied information on entomopathogenic (EPNs) and slug parasitic nematodes (SPNs) that are used or have potential in the management of insect pests, molluscs and/or other researched targets such as plant parasitic nematodes. The information includes the remarkable developments and latest achievements in this direction. The volume is divided into seven parts. The two chapters in Part I introduce comprehensive information on beneficial nematodes in general and their importance, with emphasis on crop pest management. In Part II, there are four chapters devoted to covering the different aspects of the morphology, taxonomy, biology and diversity of EPNs. Part III deals with EPNs and their symbiotic bacteria against crop insect pests and consists of seven chapters. Four chapters describe their role in the management of such insects in the orders Lepidoptera, Coleoptera and Diptera, as well as stored grain pests. Two chapters address the toxic secretions of the EPN-mutualistic bacterial species in the two genera Xenorhabdus and Photorhabdus , and their efficacy against crop insect pests either singly or with EPNs. The last chapter of this part is devoted to the mass production, formulation and application of EPNs. Part IV addresses 11 developed and developing countries as points in case, where the role of EPNs in the integrated pest management strategies implemented in each of these countries is presented. Part V presents the genetics for enhancing the efficacy of EPNs. It contains two chapters dealing with nematode breeding, as well as classical and current methods to achieve such an enhancement. Part VI has three chapters organized for SPNs. In Part VII, there are three chapters to conclude the potential commercialization and future prospects of EPNs and SPNs.
Cyclocephaline scarab beetles represent the second largest tribe of the subfamily Dynastinae, and the group includes the most speciose genus of dynastines, Cyclocephala . The period following publication of Sebő Endrődi’s The Dynastinae of the World has seen a huge increase in research interest on cyclocephalines, and much of this research has not been synthesized. The objective of this catalog and bibliography is to compile an exhaustive list of taxa in Cyclocephalini. This paper provides an updated foundation for understanding the taxonomy and classification of 14 genera and over 500 species in the tribe. It discusses the history of cataloging dynastine species, clarifies issues surrounding the neotype designations in Endrődi’s revision of Cyclocephalini, synthesizes all published distribution data for cyclocephaline species, and increases accessibility to the voluminous literature on the group by providing an easily searchable bibliography for each species. We propose the nomen novum Cyclocephalarogerpauli , new replacement name , for C.nigra Dechambre.
Asiatic garden beetle (AGB): Maladera castanea (Arrow) European chafer (EC): Rhizotrogus (Amphimallon) majalis (Razoumowsky) Japanese beetle (JB): Popillia japonica Newman Square plots (10 ft wide) were established as a six-replicate, seven-treatment RCBD in 36-inch tall field-grown hemlocks planted at 3.3-ft spacing in West Suffield, CT. Sprays were applied at 35 gpa to the bare soil surface on 6 Jun with a CO 2-pressurized (30-psi) research sprayer. Conditions were: 63° F, with heavy rain, and a 0-5 mph wind; fine sandy loam soil with 62.7% sand, 30.1% silt, 7.2% clay, 4% organic matter, and a pH of 6.1. White grub populations were assessed on 6 Sep (92 d after treatment) by removing 10, 4-inch-diameter soil cores from close to the dripline of the center four shrubs of each plot. The composited sample was sifted to remove, identify and count the white grubs. Means were separated with the Student-Newman-Kuels (SNK) test (P < 0.05). All treatments were very effective at reducing the numbers of EC. There were no differences between imidacloprid and thiamethoxam, nor was there any dosage effect. All insecticide-treated plots would have passed the phytosanitary certification standard as being free of JB larvae.
Asiatic garden beetle (AGB): Maladera castanea (Arrow) European chafer (EC): Rhizotrogus (Amphimallon) majalis (Razoumowsky) Oriental beetle (OB): Exomala orientalis (Waterhouse) Rectangular plots (20 × 10 ft) were established as a four-replicate, four-treatment RCBD in 24-inch tall field-grown burning bush planted at a 40 × 36-inch spacing in Southwick, MA. The soil was fine sandy loam and sandy loam. All sprays except Mach-2 were applied to the soil surface on 31 Aug with a CO 2-pressurized (40-psi) research sprayer. Conditions were 82° F with a 0-3 mph wind. Merit and thiamethoxam (CGA-293343) were applied as a band treatment over the row to heat 1/2 the surface area of their plots, in a volume of 26 gpa, and lightly cultivated. Mach-2 was applied by the grower to the remainder of the field as a broadcast spray on 1 Sep using a boom sprayer in a volume of 24 gpa. White grub populations were assessed on 24 Oct 54 d after treatment by digging three shrubs from each plot and sifting the soil from around the root systems to remove, identify, and count the white grubs. Means were separated with the Student-Newman-Kuels test (P < 0.05). There were low larval counts in all treatments. Merit and Mach-2 significantly reduced EC populations. Curative treatments were ineffective at reducing the numbers of the principal target pest, OB, despite banding the insecticides to essentially double the normal use rate.
Grubs of the scarabaeid Cyclocephala hirta infected with the milky disease bacterium, Bacillus popilliae (Bp), were more susceptible to the entomopathogenic nematodes Heterorhabditis bacteriophora and Steinernema glaseri than healthy grubs. Increased susceptibility was due to greater ease of nematode penetration through the midguts of Bp-infected insects and occurred after > 10 days exposure to B. popilliae spores. By that time, the bacterium was proliferating rapidly in the insect hemolymph and possibly stressed the insect by physiological starvation. Attraction of the nematodes to the insects and cuticular penetration by the nematodes were ruled out as possible reasons for the enhanced susceptibility of Bp-infected grubs. In greenhouse pot trials, S. glaseri killed more Bp-infected grubs than healthy grubs, whereas no differences were noted with H. bacteriophora. Thus, to achieve the best grub control in the presence of B. popilliae, application of S. glaseri is recommended. The compatibility of B. popilliae and entomopathogenic nematodes in the field is ensured by the existence of a diseased insect class with a low level of susceptibility to the nematode, the presence of B. popilliae in grubs not interfering with nematode progeny production, and the ability of B. popilliae spores to survive invading nematodes and their associated bacteria.
In an examination of entomopathogenic nematodes used in inundative releases on turfgrass against Japanese beetle larvae, Popillia japonica Newman, 380 treatments from 82 field trials performed from 1984 to 1988 were analyzed using a standard protocol. The results show that most test failures can be explained on the basis of unsuitable nematode strains or environmental conditions. Steinemema carpocapsae (Weiser) appears ill-adapted to parasitize Japanese beetle larvae under any range of conditions. By contrast, theHP88strain of Heterorhabditis bacteriophora Poinar, produced on solid media, provides control comparable with that by chemical insecticides at the appropriate season (fall), soil temperature ( >200 <:), soil type (silty clay), irrigation frequency (1-4-d intervals), and thatch depth «10mm). The importance of multiple tests that can be analyzed is discussed. Standardized procedures are recommended for field testing; if widely adopted, they would permit comparisons between trials and the generation of large data sets needed for developing statistical models.
Imidacloprid, a chloronicotinyl, and halofenozide, a bisacylhydrazine ecdysteroid agonist, recently have become widely used for residual control of scarabaeid grubs in turf. We evaluated their impact on earthworms and beneficial arthropods in field trials, and tested whether application in late spring might interfere with subsequent predation on black cutworm, Agrotis ipsilon (Hufnagel), and Japanese beetle, Popillia japonica Newman, life stages in Kentucky bluegrass, Poa pratensis L., turf. Bendiocarb, a short-residual carbamate, was included for comparison. Imidacloprid caused some short-term suppression of earthworms, whereas bendiocarb had severe impact on earthworms, mesostigmatid mites, and Collembola. Pitfall trap captures of predatory coleopteran larvae and hister beetles were reduced by imidacloprid and bendiocarb, but abundance of ants, carabids, spiders, and staphylinids was largely unaffected. Halofenozide caused no reduction in abundance of any group of beneficial invertebrates. Scavenging on fresh-frozen A. ipsilon larvae was reduced for ≈1 wk after use of imidacloprid or bendiocarb, but predation rates on eggs or pupae of A. ipsilon, and on implanted P. japonica eggs, were unaffected. This work suggests that application of halofenozide or imidacloprid, followed by irrigation, will have relatively little impact on beneficial invertebrates, although both compounds are persistent enough to control P. japonica and Cyclocephala spp. grubs eclosing several months later.
In previous greenhouse studies, the insecticide imidacloprid and the entomopathogenic nematode Heterorhabditis bacteriophora Poinar interacted synergistically against third instars of the masked chafers Cyclocephala hirta LeConte and C. pasadenae Casey (Coleoptera: Scarabaeidae). We tested this interaction for two additional nematode species and three additional scarab species under field conditions. In greenhouse tests, H. bacteriophora and Steinernema glaseri (Steiner) interacted synergistically against third instars of the Japanese beetle, Popillia japonica Newman, the oriental beetle, Exomala orientalis Waterhouse, and the masked chafers Cyclocephala borealis Arrow, C. pasadenae, and C. hirta. The degree of interaction varied with nematode species. The strongest synergism occurred between imidacloprid and S. glaseri. Synergism between imidacloprid and H. bacteriophora was weaker and the interaction was not always significant. Combinations of imidacloprid and S. kushidai Mamiya only resulted in additive mortality. The synergistic interaction was also observed in field trials but the results were more variable than those under greenhouse conditions. The combination of nematodes and imidacloprid could be used for curative treatments of white grub infestations, especially against scarab species that are less susceptible to nematodes and/or imidacloprid. This combination has a low environmental impact and high compatibility with natural biological control of turfgrass insects. The possible roles of these combinations in augmentative control approaches are discussed.
Publisher Summary
This chapter focuses on the techniques used for identifying, isolating, propagating, assaying, and preserving nematodes that are parasitic in or pathogenic to insects. Nematodes are nonsegmented animals with excretory, nervous, digestive, reproductive, and muscular systems but lacking circulatory and respiratory systems. The stage of entomogenous and entomopathogenic nematodes that is infective varies depending on the group. A good stereomicroscope is essential for nematode identification and should have a range of magnification between 10 and 100X, a fairly fiat field, and good resolution. The gonads and other structures of fixed nematodes may be obscured by the granular appearance of the intestine. Specimens can be cleared by processing to lactophenol or glycerin. The cephalic structures and the number of longitudinal chords are diagnostic characters for genetic or specific determination of certain groups of nematodes. Extraction methods for insect nematodes are derived from techniques developed with plant-parasitic nematodes. It is found that the most common methods are the Baermann funnel, sieving, elutriation, and centrifugal flotation.
Effects of exposure to Bacillus thuringiensis and a nuclear-polyhedrosis virus (NPV) on larvae of the cabbage looper, Trichoplusia ni, were determined in laboratory experiments. Mortality curves Were established for each pathogen and served as the basis for the tests. Third-instar larvae averaging 15 mg body weight were inoculated by being on a diet containing desired concentrations of the pathogens. The ELD50 for B. thuringiensis was 300 IU/ml of diet and for NPV, 2.27 × 103 polyhedral inclusion bodies/ml of diet. Mortality data from larvae exposed to both pathogens simultaneously at generally low dosages indicated that the effects of the pathogens in combination were additive. Results from experiments in which larvae were stressed by exposure to NPV for 24-96 hr prior to exposure to B. thuringiensis showed that increased mortality was an additive effect of the two pathogens. Pupae from larvae exposed to B. thuringiensis were significantly smaller than those from larvae exposed to NPV alone or to no pathogen.
Combinations of the insecticide imidacloprid and entomopathogenic nematodes were tested for control of white grubs. In greenhouse tests, field-collected 3rd-instar white grubs were placed in pots with grass treated with imidacloprid, the entomopathogenic nematode Heterorhabditis bacteriophora (Poinar), or both. Combinations of imidacloprid and nematodes had a strong synergistic effect on mortality at imidacloprid concentrations ranging between 50 to 200 g (AI) / ha. This effect was observed when imidacloprid and the nematodes were applied at the same time or when imidacloprid was applied first followed by the nematodes 14 d later. The synergistic interaction occurred against a nematode-susceptible scarab species, Cyclocephala hirta LeConte, and against a more nematode-resistant scarab species, C. pasadenae Casey. When infective juveniles of H. bacteriophora were agitated in solutions of imidacloprid for 24 h, no negative effect on their survival and infectivity was observed.
In previous laboratory studies, entomopathogenic nematodes andBacillus thuringiensissubspeciesjaponensis(Btj) caused additive or synergistic mortality in third-instarCyclocephala(Coleoptera: Scarabaeidae) grubs when the nematodes were applied at least 7 days afterBtj.This type of mortality was observed forC. hirta,a species that is not very susceptible toBtj,and forC. pasadenae,a species that has intermediate susceptibility toBtj.In the present study, this observation was confirmed for third-instarAnomala orientalis,a species that is highly susceptible toBtj.In greenhouse and field studies, additive or synergistic interactions between nematodes andBtjwere observed for all three scarab species. The interactions were variable, and to achieve acceptable grub control, high concentrations ofBtjhad to be applied. A subsequent greenhouse experiment showed that young third-instarC. pasadenaewere more susceptible toBtjthan older third instars. In addition the interaction between nematodes andBtjwas also more synergistic in the younger than in the older third instars. In a field test against a population ofC. hirtaconsisting of late second and early third instars, combinations of nematodes andBtjat economic application rates provided acceptable control levels whether applied simultaneously or with a 4-day delay betweenBtjand nematode application. Our observations suggest that curative control of white grubs is possible with combinations of entomopathogenic nematodes andBtjif the applications are done when populations consist of second and early third instars.
The mode of action of the nitromethylene heterocycle group of insecticides was investigated in the American cockroach, Periplaneta americana. In vivo symptomology was characterized by a definite sequence of events, starting with abdominal quivering and followed, in order, by wing flexing, uncontrollable preening, leg tremors, violent whole body shaking, prostration, and death. Neurophysiological experiments showed that the nitromethylene heterocycles have dramatic effects on nerve impulse transmission at the cholinergic cercal nerve-giant fiber synapses located within the cockroach sixth abdominal ganglion. The effects were biphasic and were characterized by an initial increase in the frequency of spontaneous giant fiber discharges, followed by the development of a complete block to nerve impulse propagation. The nitromethylene heterocycles did not inhibit insect cholinesterase. Neuropharmacological experiments showed that the specific site of action was postsynaptic, and probably involved an agonistic effect on postsynaptic acetylcholine receptors.
We studied the interactions betweenBacillus thuringiensissubspeciesjaponensisBuibui strain (Btj) and entomopathogenic nematodes on the white grubs,Cyclocephala hirtaandC. pasadenae.Field-collected third instar grubs were kept individually in microcosms filled with soil and fed grass seeds. Grubs were exposed to various concentrations ofBtjand/or entomopathogenic nematodes and grub mortality was assessed at weekly intervals. Nematodes were added at 0 to 14 days after application ofBtj.Throughout most of our experiments, combinations ofBtjand nematodes caused additive grub mortalities or greater than additive mortalities, indicating synergism. To achieve additive or synergistic effects, grubs had to be exposed toBtjfor at least 7 days before the addition of nematodes. We observed this interaction betweenBtjandHeterorhabditis bacteriophoraorSteinernema glaseri,but not with the most pathogenic nematode,S. kushidai.The additive or synergistic interaction betweenBtjandS. glaseriorH. bacteriophoramay offer a powerful and reliable tool for scarab grub control.
Entomopathogenic nematodes and the chloronicotinyl insecticide, imidacloprid, interact synergistically on the mortality of third-instar white grubs (Coleoptera: Scarabaeidae). The degree of interaction, however, varies with nematode species, being synergistic for Steinernema glaseri (Steiner) and Heterorhabditis bacteriophora Poinar, but only additive for Steinernema kushidai Mamiya. The mechanism of the interaction between imidacloprid and these three entomopathogenic nematodes was studied in the laboratory. In vials with soil and grass, mortality, speed of kill, and nematode establishment were negatively affected by imidacloprid with S. kushidai but positively affected with S. glaseri and H. bacteriophora. In all other experiments, imidacloprid had a similar effect for all three nematode species on various factors important for the successful nematode infection in white grubs. Nematode attraction to grubs was not affected by imidacloprid treatment of the grubs. Establishment of intra-hemocoelically injected nematodes was always higher in imidacloprid-treated grubs but the differences were small and in most cases not significant. The major factor responsible for synergistic interactions between imidacloprid and entomopathogenic nematodes appears to be the general disruption of normal nerve function due to imidacloprid resulting in drastically reduced activity of the grubs. This sluggishness facilitates host attachment of infective juvenile nematodes. Grooming and evasive behavior in response to nematode attack was also reduced in imidacloprid-treated grubs. The degree to which different white grub species responded to entomopathogenic nematode attack varied considerably. Untreated Popillia japonica Newman (Coleoptera: Scarabaeidae) grubs were the most responsive to nematode attack among the species tested. Untreated Cyclocephala borealis Arrow (Coleoptera: Scarabaeidae) grubs showed a weaker grooming and no evasion response, and untreated C. hirta LeConte (Coleoptera: Scarabaeidae) grubs showed no significant response. Chewing/biting behavior was significantly increased in the presence of nematodes in untreated P. japonica and C. borealis but not in C. hirta and imidacloprid-treated P. japonica and C. borealis. Our observations, however, did not provide an explanation for the lack of synergism between imidacloprid and S. kushidai.
Routes by which nontarget predatory insects can be exposed to turfgrass pesticides include topical, residual, and dietary exposure. We used each of these routes to evaluate potential lethal or sublethal effects of two novel turfgrass insecticides, imidacloprid and halofenozide, and a carbamate, bendiocarb, on survival, behavior, and fecundity of the ground beetle Harpalus pennsylvanicus DeGeer. Field-collected carabids were exposed to direct spray applications in turf plots, fed food contaminated by such applications, or exposed to irrigated or nonirrigated residues on turf cores. Halofenozide caused no apparent acute, adverse effects through topical, residual, or dietary exposure. Moreover, the viability of eggs laid by females fed halofenozide-treated food once, or continuously for 30 d, was not reduced. In contrast, topical or dietary exposure of carabids to bendiocarb inevitably was lethal. Exposure to imidacloprid by those routes caused high incidence of sublethal, neurotoxic effects including paralysis, impaired walking, and excessive grooming. Intoxicated beetles usually recovered within a few days in the laboratory, but in the field, they were shown to be highly vulnerable to predation by ants. One-time intoxication by imidacloprid did not reduce females' fecundity or viability of eggs. There was no apparent behavioral avoidance of insecticide residues, or of insecticide-treated food. Carabids exposed to dry residues on turfgrass cores suffered high mortality from bendiocarb, and some intoxication from imidacloprid, but these effects were greatly reduced by posttreatment irrigation. Implications for predicting hazards of insecticides to beneficial invertebrates in turfgrass are discussed.
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