Interaction of Insecticides, Entomopathogenic Nematodes, and Larvae of the Western Corn Root worm (Coleoptera: Chrysomelidae)

Implications of Swede Midge Biology in the Development of Population Management Alternatives

Thesis

Full-text available

Dec 2017

Braden Evans

The swede midge, Contarinia nasturtii, is a significant pest of cruciferous crops in Canada and the United States. Though some control has been achieved with chemical pesticides, there is a need to evaluate alternative tactics for organic producers. The purpose of this study is to examine how C. nasturtii life history traits impact the potential success of alternative control tactics. The effect of temperature on three entomopathogenic nematode species, and one entomopathogenic fungus were investigated. Successful reproduction and infectivity were observed in all nematode species and a nematode-fungus combination generally caused highest mortality to all C. nasturtii life stages. The fungus suppressed emergence from soil in 2012 and all nematode treatments suppressed emergence in 2013 in broccoli fields. Biopesticides were evaluated for larval mortality and oviposition deterrence in the greenhouse, and damage symptoms in the field. In greenhouse trials, treatments resulted in significant reductions, with a greater proportion of reductions attributable to oviposition deterrence than larvicidal activity. Field trials showed the potential for biopesticides to reduce feeding damage; however, efficacy was dependent on C. nasturtii abundance. Insect exclusion fencing and planting dates were evaluated as tactics to reduce C. nasturtii damage through spatial and temporal avoidance. Fencing increased the number of marketable plants when plots were separated from fields infested with C. nasturtii by ~800 m, but no effect was observed with lower spatial separation. A survey of flight height produced observations of adults flying 240 cm above the soil, which is above the height of the fencing. Reduced damage was observed in late broccoli plantings and early cabbage plantings, while traditional planting dates suffered total yield losses. The population model MidgEmerge was evaluated for prediction accuracy of spring emergence, and sensitivity to temperature, rainfall, and model parameters. Predictions were early during hot, dry years, and late during cool, wet years. Temperature affected model output, but rainfall did not. Manipulating thresholds for ‘diapause larva development temperature’, and ‘minimum temperature for pupal growth’ resulted in changes to predicted emergence. Prediction by MidgEmerge potentially overstates the effect of temperature, and understates the effect of rainfall. Recommendations to improve model accuracy are provided.

ENTOMOPATHOGENIC NEMATODES : A HIDDEN ENEMY OF INSECT PESTS

Article

Full-text available

Apr 2017

Entomopathogenic nematodes (EPN’s) are attractive, organic alternatives for controlling a wide range of insect pests and they are utilized in classical, conservation and augmentative biological control programs. The history of entomopathogenic nematology is briefly reviewed. In general, EPN’s are soil borne and generally gets mutually associated with a bacterium which is responsible for pesticidal actions and its life cycle of consist of five developmental stages. The two most studied species of EPN’s are Steinernematidae and Heterorhabditidae families which has mutualistic association with bacteria of genus Xenorhabdus and Photorhabdus, respectively. The virulence mechanisms of the symbiotic bacteria were depending upon antibiotic properties, phase variants and impeding host defense responses. In the laboratory use and small scale field experiments, in vivo production of EPNs appears to be the appropriate method. In vitro technology is used when large scale production is needed at reasonable quality and cost. The efficacy of EPNs can be enhanced through proper production technology, storage mechanism, application technology etc. The scientific community, academician and industrialist are interest to development of new bio-insecticides, which are environmentally friendly. The concerns for the environment and human health and to reducing the risks connected with chemicals, the present review article focused on importance of EPN’s in insect pests management, its life cycle, virulence mechanism, mass production technology, commercial product and storage, application technology, guideline for field application and its ccompatibility with insecticide and fertilizers are briefly reviewed.

From proof of concept to optimization - the use of a predatory mite species to control the population of the Western Corn Rootworm (Diabrotica virgifera virgifera) (LeConte, 1868)

Thesis

Dec 2021

Antoine Pasquier

Maize is the most important cereal crop in the world (162 million hectares). It plays a major role in human and animal nutrition and its cultivation occupies about 9% of the useful agricultural area in Europe. Since its arrival in Europe in 1992, the corn rootworm, belonging to the order Coleoptera, has threatened this important crop. The larval stage of this organism is particularly harmful to plants because it attacks the underground parts of this cereal causing yield losses that can reach 80% of the crop's potential in the most critical cases. Chemical pesticides, the use of Bt GMOs and crop rotation alternating soybeans and corn are the main control methods for this pest currently. However, studies have shown that some populations are resistant to these insecticides and are able to (i) persist in the soil longer and (ii) expand their host range by attacking soybean roots. In this context, there is a need to explore new crop protection methods that will allow a more integrated control of this pest. A study recently demonstrated the potential role of soil predatory mites as biological control agents. These organisms are at the top of trophic chains in agricultural systems and have already shown strong abilities to control populations of subterranean pests. The main objective of my thesis is to develop a biological control strategy agronomically and economically viable to control corn rootworm. First, I evaluated the predation capacity of three soil mites (Stratiolaelaps scimitus, Gaeolaelaps aculeifer and Macrocheles robustulus) on the early developmental stages of western corn rootworm in the laboratory. These results were conclusive and one of the three candidates particularly attracted our attention: G. aculeifer. This predatory mite showed a higher predation capacity on the first larval stage of the pest. In a second step, I studied the effect of the presence and the density (100, 500 and 1000 mites per corn plant infested by the pest) of these predatory mites on the western corn rootworm population under semi-controlled conditions.This experiment showed that the mite densities tested were all effective in protecting the maize plant. Finally, and in order to optimize the effectiveness of these predatory mites as a biocontrol agent, I studied the population dynamics of these predators when a low density of predatory mites has been introduced at the time of seeding (Predator-in-first method) and in the presence of alternative food, in a field naturally infested by corn rootworm. These experiments allowed me to identify an application method that would facilitate the introduction of the biological control solution and reduce its cost. My work will provide essential information in understanding the biological control potential of these previously understudied soil organisms.

The aggregation pheromone phenylacetonitrile: Joint action with the entomopathogenic fungus Metarhizium anisopliae var. acridum and physiological and transcriptomic effects on Schistocerca gregaria nymphs

Article

Apr 2020

The combined use of entomopathogenic fungi and sublethal rate of chemical insecticides or other biological control agents have been proposed as an environmentally and sustainable strategy in the control of locust pests. In this paper, the quarter and the half of the recommended dose of Metarhizium anisopliae var. acridum (¼ and ½ Ma) and the aggregation pheromone (Phenylacetonitrile: PAN) were applied simultaneously and sequentially to Schistocerca gregaria fifth-instar nymphs. In addition, the physiological effects of PAN on locusts were assessed at the behavior, immune response, and biochemical level by evaluating for glutathione-S-transferase (GST), acetylcholinesterase inhibition (AChE), and malondialdehyde accumulation (MDA). Results showed that simultaneous application of PAN and the entomopathogenic fungus exhibited additive interaction. Synergistic interaction was also demonstrated when nymphs were exposed to PAN first, then treated with M. anisopliae var. acridum. Behavioral bioassay revealed that fifth-instar nymphs avoided the PAN odour and tended to remain away from the stimulus cup. In the choice assay, the pheromone significantly repelled the locusts at 2, 4, and 6 h of exposure which selected the PAN-free arena chamber. Moreover, treated nymphs become hyperactive and disoriented as evidenced by the cumulative distance travelled and the trajectory of locusts during the experiment. Immunological studies showed that PAN significantly decreased the differential haemocyte counts (prohemocytes and plasmatocytes) with a dose-response relationship. Data of biochemical analyzes showed that the PAN exposure reduced the activity of acetylcholinesterase and induced significantly the glutathione S-transferases and MDA concentration in the desert locust fifth-instar nymphs. Moreover, transcriptomic responses to the PAN exposure were evaluated using gene expression levels of CYP540 and GST. The transcript levels showed an up-regulation in GST expression level particularly in nymphs exposed for 4 and 6 h. A significant increase in CYP450 transcript level was also observed after 2 h of exposure, which decreased significantly after 4 and 6 h.

Comparative efficacy of Steinernema carpocapsae with insecticide and bio-pesticides against Spodoptera litura infecting brinjal

Article

Full-text available

Sep 2016

An experiment was conducted under pot condition to find out the combined effect and comparative efficacy of S. carpocapsae with insecticide and bio-pesticides against tobacco caterpillar infecting brinjal. One half and one fourth of recommended dose of pesticides (Cypermethrin, spltNPV and NSKE) with 25000 IJs of S. carpocapsae per plant were inoculated and the per cent mortality was recorded every day after spraying up to 10 days. Results showed that splt NPV, NSKE and Cypermethrin alone at one half doses each caused less mortality of S. litura viz. 40, 40 and 55 per cent, respectively, than when combined with EPN's (95%). The experimental results revealed that maximum (95.0) per cent mortality was observed within 5 days after spraying with combination of 25000 IJs of S. carpocapsae and one half dose of Cypermethrin, while individually they caused 75 and 55 per cent mortality, respectively. After 6 days of spraying 30 and 80 per cent mortality was observed at one half dose of NSKE and 25000 IJs alone, while it was 95 per cent in combination. 95 per cent mortality also observed with combined application of one half dose of spltNPV and 25000 IJs within 7 days after spraying, while EPN's alone caused 85 per cent mortality and no mortality was observed by spltNPV alone after 5 days. Thus, from present investigation, it is advocated that combinations of NSKE, spltNPV and Cypermethrin with S. carpocapsae were more effective against S. litura than individual application.

CHARACTERIZATION OF THE NATURAL ENEMY COMMUNITY, WITH EMPHASIS ON ENTOMOPATHOGENS, FOR MANAGEMENT OF WESTERN CORN ROOTWORM ( DIABROTICA VIRGIFERA VIRGIFERA ) IN WEST CENTRAL NEBRASKA

Article

Aug 2018

Camila Oliveira-Hofman

Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae),the western corn rootworm (WCR), is a major pest of corn (Zea mays L.) in the United States and Europe. WCR management options comprise mainly transgenic hybrids, insecticide applications and crop rotation. WCR is highly adaptable to management practices and field-evolved resistance to transgenic corn, insecticides and crop rotation in the United States Corn Belt has been reported. Therefore, the motivation for this project was to look into alternative options for WCR management. The goal of this dissertation is to characterize the natural enemies from irrigated commercial cornfields in Nebraska and examine their potential as biological control agents of the WCR. We surveyed five cornfields to document populations of arthropod predators, entomopathogenic fungi (EPF) and entomopathogenic nematodes (EPN). Yellow sticky cards and dry pitfalls captured a diverse community of above-ground natural enemies but their impact on WCR population dynamics is unlikely. In the laboratory, we isolated EPF and EPN species from soil samples using a baiting technique with Galleria mellonella L. andTenebrio molitor L. Entomogenous fungi with a variety of ecological roles were detected in every cornfield. Entomopathogenic fungi made up the majority of isolates, primarily represented by Metarhizium, but other genera of known and potential EPF include Beauveria, Penicillium, Pseudogymnoascus, and Purpureocillium. In the laboratory, forty-eight strains were screenedagainst WCR larvae. Results showed thatMetarhizium anisopliae, M. robertsii, Pseudogymnoascussp. and BotaniGard (Beauveria bassiana) caused mortality higher than the control and should be explored further in field studies. Six strains that were tested against the WCR can also infect prepupae of western bean cutworm (Striacosta albicostaSmith), another damaging pest of corn in Nebraska. We also determined that EPN strains of Heterorhabditis bacteriophoraPoinar andSteinernema spp. are present in Western Nebraska cornfields. An inoculation project with commercial and New York strains of EPN did not cause significant mortality in WCR populations, potentially due to native Steinernemaspp. being present in the control plots. Describing the natural enemy community from WCR-infested fields is a necessary first step in the exploration of biological control as a management tool against this devastating pest. Advisors: Julie A. Peterson and Lance J. Meinke

Status of entomopathogenic nematodes in integrated pest management strategies in Egypt

Chapter

Jul 2017

Mahfouz Abd-Elgawad

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.

Control of Stored Grain Pests by Entomopathogenic Nematodes

Chapter

Jul 2017

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.

Quantifying synergistic interactions: a meta-analysis of joint effects of chemical and parasitic stressors

Article

Full-text available

Aug 2023

The global biodiversity crisis emphasizes our need to understand how different stressors (climatic, chemical, parasitic, etc.) interact and affect biological communities. We provide a comprehensive meta-analysis investigating joint effects of chemical and parasitic stressors for 1064 chemical-parasitic combinations using the Multiplicative model on mortality of arthropods. We tested both features of the experimental setup (control mortality, stressor effect level) and the chemical mode of action, host and parasite phylogeny, and parasite-host interaction traits as explanatory factors for deviations from the reference model. Synergistic interactions, defined as higher mortality than predicted, were significantly more frequent than no interactions or antagony. Experimental setup significantly affected the results, with studies reporting high (> 10%) control mortality or using low stressor effects (< 20%) being more synergistic. Chemical mode of action played a significant role for synergy, but there was no effects of host and parasite phylogeny, or parasite-host interaction traits. The finding that experimental design played a greater role in finding synergy than biological factors, emphasize the need to standardize the design of mixed stressor studies across scientific disciplines. In addition, combinations testing more biological traits e.g. avoidance, coping, and repair processes are needed to test biology-based hypotheses for synergistic interactions.

Potential of entomopathogenic nematode‐infected insect cadavers for the biocontrol of the red imported fire ant Solenopsis invicta

Article

Full-text available

Jul 2023
PEST MANAG SCI

Background Entomopathogenic nematodes (EPNs) in an aqueous suspension treatment showed potential in the biocontrol of the red imported fire ant Solenopsis invicta, whereas colony relocation following this inundative application had restricted overall effectiveness. As a novel strategy, EPN pre‐infected insect cadavers carrying the next generation of nematode‐infective juveniles (IJs) might be used to efficiently manage insect pests. However, this strategy has not been tested on S. invicta. This study evaluated EPNs emerging from wax moth Galleria mellonella cadavers to facilitate infection of S. invicta compared to those used in aqueous suspensions. Results Among seven EPN species, Steinernema riobrave and Heterorhabditis bacteriophora had the highest insecticidal efficiency in aqueous treatment. Cadavers of G. mellonella colonized by either one of two EPN species were not damaged by worker ants, ensuring that the IJs could develop within and emerge successfully from the cadavers. Likewise, compared to an aqueous suspension treatment with an equivalent number of IJs, treatment with an S. riobrave‐infected cadaver increased the mortality of S. invicta by ≈10%, whereas infection by H. bacteriophora did not differ between treatments. However, the coexistence of S. riobrave‐ and H. bacteriophora‐infected cadavers adversely affected the control of S. invicta, likely as a result of competition resulting from the increased dispersal of each emerging EPN species. Conclusion Using EPN‐infected G. mellonella cadavers as a strategy increased the mortality of S. invicta in the laboratory. This study provides positive evidence for the future applications of S. riobrave‐infected cadavers in the biocontrol of red imported fire ants. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Role of Entomopathogenic Nematodes in Organic Farming and Sustainable Development

Chapter

Full-text available

Jun 2023

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.

Nematicidal Effects of Four Terpenes Differ among Entomopathogenic Nematode Species

Article

Full-text available

May 2023

Entomopathogenic nematodes (EPNs) have been studied for more than half a century, and employed for insect pest management using augmentation, conservation, and classical biological control approaches. As obligate lethal parasitoids of insect larvae, EPN navigate a chemically complex soil environment and interact with their insect hosts, plants, and each other. EPN responses to various terpenes, such as herbivore-induced plant volatiles, have the potential to enhance EPN efficacy through their attraction. However, several of the terpenes are currently being formulated as biological fungicides, insecticides, and acaricides for above- or below-ground applications. We conducted laboratory experiments to investigate the possible nematicidal effect of four terpenes, carvacrol, geraniol, eugenol, and thymol, to two heterorhabditids and two steinernematid species. Each terpene showed nematicidal activity against at least two of the four EPN species, with carvacrol showing the strongest activity and Heterorhabditis bacteriophora the highest sensitivity. Despite the high sensitivity of both heterorhabditids and near-zero sensitivity of the steinernematids to thymol, carvacrol, and eugenol, an increasing effect was observed when steinermatid nematodes were exposed to geraniol, and a decreasing effect for heterorhabditids, with H. bacteriophora exhibiting higher mortality than H. indica. The virulence of the nematodes towards fourth instar Galleria mellonella was also tested after exposure to the median lethal doses of each terpene. No significant difference in virulence was observed between nematodes that were exposed or not exposed to sublethal doses. The experiments suggest that the tested terpenes have a strong effect on EPN viability, which should be considered when combining the two approaches in IPM. The terpenes did not have a universal effect on all nematode species, which merits further investigation, while virulence tests suggest that sublethal doses of these terpenes have no effect on the host-killing performance of EPNs.

Pathogenicity of entomopathogenic nematodes against the new invasive fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae)

Article

Full-text available

Feb 2023

Background Fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is the new invasive pest of different economic crops, threatening the agricultural economy worldwide. Chemical insecticides are the main control management strategy applied by almost farmers. As the adverse effect of these chemicals on the environment and human health, improving alternative environmentally friendly control against this pest is urgently needed. In this response, the pathogenicity bioassays of 2 entomopathogenic nematode species (EPNs), Steinernema carpocapsae (All) and Heterorhabditis indica (EGAZ2), on different FAW larval instars (2nd to 6th instars) were assessed under laboratory conditions. Results The results cleared that FAW larval mortality rate was varied significantly related to nematode species, post-exposure times and developmental instar stages. S. carpocapsae application was more virulent and effective against all tested instars larvae, registering 100% mortality after 48–72 h post-exposure at different nematode concentrations (150–2400 IJs). However, H. indica caused 100% mortality in early instars only after 96 h, but late instars required a longer time extending to 120–188 h at tested concentrations. In this context, 2nd and 3rd instars were highly susceptible to Heterorhabditis species infection. Lower nematode concentrations (150–300 IJs) caused moderate mortality 33.33–50%, respectively, in 5th and 6th full-developed larvae only. All recovery larvae post-infection died in the pupal stage or adult emerged with wing malformation. Conclusion The 2 EPN species were virulent against different FAW larval instars at different concentrations and exposure times. Thereby, they are recommended as biocontrol agents against this invasive pest, particularly S. carpocapsae after low-exposure time. This study provides essential information on EPNs, which will further help in the practical application of biological control against fall armyworm.

Recent Advances and Current Status in the Rice Pest Management in Sri Lanka.

Chapter

Dec 2022

Application of Fungal Biocontrol Agents for the Management of Plant Parasitic Nematodes

Chapter

Dec 2022

Dealing with different biocontrol agents for the management of plant parasitic nematodes

Entomopathogenic nematode species combinations alter rates of dispersal, host encounter and insecticidal efficiency

Article

Full-text available

Jun 2022
J PEST SCI

Combinations of entomopathogenic nematode (EPN) species are sometimes more or less effective than individual species for the management of insect pests. We hypothesized that these outcomes are due in part to dispersal rates that differ when EPN species are conspecific or heterospecific. Dispersal rates of three heterorhabditid species, six steinernematid species, and mixtures of some were assessed using image analysis of nematodes on water agar. The dispersal rates between the genera differed significantly and were unrelated to the estimated body mass or the putative foraging strategy, including that of the recently named Steinernema khuongi, characterized here as a cruise forager (actively search for hosts). Heterorhabditis indica dispersed more rapidly on agar when combined with S. diaprepesi, but not with S. glaseri. The presence of S. diaprepesi in soil microcosms also increased the proximity of H. indica to Galleria mellonella host insects, while H. indica presence reduced the number of G. mellonella killed by S. diaprepesi. Nevertheless, increasing the H. indica dispersal rate did not increase its insecticidal effectiveness, likely due to competition with the more virulent S. diaprepesi. Rather, the effect of combining the species on the mortality of G. mellonella was additive. Our results suggest that interspecific EPN communication affects not only orientation but also dispersal rate, with potential impacts on biological control and the subsequent fitness of each species.

Compatibility (in vitro) of entomopathogenic nematode, S. carpocapsae with botanicals

Research

Full-text available

Jan 2019

Compatibility of S. carpocapsae with nimibicidine and kalmegh extract was tested in laboratory condition. Different doses of nimibicidine at 0.05, 0.10 per cent and kalmegh extract 5 & 10 per cent were used. The observation on per cent mortality revealed that S. carpocapsae were found compatible with different botanicals i.e. nimibicidine and kalmegh extract at different doses i.e. 0.05, 0.10 per cent and 5 & 10 percent, respectively. On the basis of their per cent mortality after 12 to 60 hrs the minimum per cent mortality of S. carpocapsae was observed 23.63 and 25.38 with nimibicidine at 0.05 & 0.10 per cent after 60 hrs. The EPN, S. carpocapsae was found compatible with nimibicidine and kalmegh extract upto varying degree.

A Promising Predator-In-First Strategy to Control Western Corn Rootworm Population in Maize Fields

Article

Full-text available

Sep 2021

Western Corn Rootworm is a pest of maize that mostly damages roots. Many alternative strategies have been explored to control this species, with little or non-lasting success, and it remains a threat to maize production worldwide. Gaeolaelaps aculeifer, a soil-dwelling predatory mite that inhabits the first few centimeters of the soil, showed high predatory potential against WCR larvae in the laboratory. In this study, we explored the efficiency of G. aculeifer against WCR in more realistic contexts. First, we infested maize plants isolated in pots in a greenhouse with WCR, and tested the impact of different densities of mites on plant protection. Using standard indicators of WCR population presence and impact, we confirmed that G. aculeifer has the potential to control WCR at densities starting from 100 mites/plant. Then, considering that the release of a large amount of biocontrol agents at WCR emergence might be too costly and constraining for large-scale implementation, we tested the efficiency of a predator-in-first strategy in a maize field infested by WCR. The goal was to introduce fewer G. aculeifer combined with Aleuroglyphus ovatus eggs as an alternative food source in order to let the mite population grow in the field and reach sufficient density at the critical stage for protection. This strategy gave comparable results to pesticide on all indicators examined in our field trial, highlighting the potential to sustainably manage this pest.

The impact of chemical nematicides on entomopathogenic nematode survival and infectivity

Article

Full-text available

Jun 2021
J NEMATOL

Entomopathogenic nematodes (EPNs) belonging to the genera, Steinernema and Heterorhabditis, occur naturally in the soil along with plant-parasitic nematodes which are important root pests of many different crops. Here, we report the effects of four registered nematicidal compounds (fluopyram, fosthiazate, metam potassium, and fenamiphos) that are used for the control of PPNs on the survival, virulence, penetration efficiency, and reproduction of S. carpocapsae and H. bacteriophora. Despite previous studies warning of the impact of nematicidal compounds on IJ survival and infectivity, none have assessed their impact on EPN chemotaxis, penetration into and reproduction in insect host or conducted longer term soil assays. Survival of EPNs, based on observing IJ movement under a stereomicroscope after incubation in different concentrations of nematicides, showed that ≥ 80% of both nematode species were killed by fosthiazate, fenamiphos and metam potassium within 24 h. The recommended concentration of fluopyram killed 33% of H. bacteriophora, and 28% of S. carpocapsae after 48 h exposure. IJs exposed to the nematicides were less virulent against Galleria mellonella larvae in sand bioassay to non-treated IJs as significantly more control IJs of both EPN species penetrated their insect host (~47% of IJs added) than IJs exposed to fluopyram and fosthiazate; and the number of IJ progeny emerging from these controls was significantly higher than the number of IJ progeny emerging from IJs treated with the nematicidal compounds. In a highly novel discovery, the chemotaxis experiments using Pluronic F-127 gel indicated that H. bacteriophora were repelled from nematicide-treated environ-ments. Moreover, IJs of both species added to treated natural loamy-clay soil at 5-day-intervals for 30 days post application of nematicides were generally unable to induce G. mellonella mortality, except for S. carpocapsae IJs added to fosthiazate-treated soil. Overall, our study indicates that there were detrimental effects of the nematicides on EPN IJs in treated soil. Therefore, overlap in timing for control of PPNs and the use of EPNs for biological insect control must be avoided. Future studies should assess the optimization of timing for nematicides use and survival and infectivity of IJs in the soil.

In Vitro Compatibility and Combined Efficacy of Entomopathogenic Nematodes with Abamectin and Imidacloprid Against the White Grub, Pentodon bispinosus Kust.

Article

Full-text available

Feb 2021

One of the challenges in mixing entomopathogenic nematodes (EPNs) with chemical control is low predictable compatible information; hence, pesticides are misused by farmers. Therefore, the study aimed to clarify the result of mixing abamectin and imidacloprid on the infectivity of EPNs against larvae of hard-black beetle Pentodon bispinosus Kust., besides, investigating the fluctuations of the joint action of EPN species and chemical pesticides during the study period. Recommended dose (RD) of imidacloprid (LT50= 5.20 and 14.20 d) was more efficient comparing with abamectin (LT50= 18.14 and 24.22 d) on the first third and instar larvae of white grubs. Heterorhabditis bacteriophora (Ar-4) showed the highest tolerance (LT50=10.11 and 6.22 d) while Steinernema feltiae (Filipjev) was the most sensitive (LT50=5.53 and 3.55 d) after exposure to abamectin and imidacloprid at RD, respectively. EPNs plus chemical insecticides combinations on first instar larvae recorded the higher median lethal concentration (LC50) except S. feltiae (Filipjev) plus abamectin and all combinations of EPNs with imidacloprid. All combinations with EPNs showed lower LC50 values than EPN alone except abamectin with some tested H. bacteriophora with III instar larvae. Based on LC50 values, all EPNs combinations with imidacloprid surpassed EPN alone or abamectin combinations. Moreover, mortality reached 100% in the 1st instar of white grubs at concentration 250 IJs/larva H. bacteriophora (HP88 strain) compared with 92% in the 3rd instar larvae at the same concentration after 4 weeks of incubation. The potentiation effect was observed after one week in the 3rd instar larvae only when abamectin combined with H. bacteriophora (Ar-4 strain) and S. carpocapsae (All strain) while after 3 weeks with 1st instar larvae in combination between S. feltiae (Filipjev) and the RD of abamectin and imidacloprid at concentration 150 IJs/larva. No synergistic interaction was observed in combinations of EPNs with neither abamectin nor imidacloprid. During mixing chemical pesticides and bioagents, the chemical pesticide is the independent variable effect on EPNs viability and infectivity which is affected by combining period and species. The final interaction mainly depends on the chemical pesticide selectivity and toxicity to target insects (stage and instar).

Automatic Field Detection of Western Corn Rootworm (Diabrotica virgifera virgifera; Coleoptera: Chrysomelidae) with a New Probe

Article

Full-text available

Aug 2020

The Western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a significant invasive pest of maize plantations in Europe. Integrated pest management demands an adequate monitoring system which detects the activity of insects with high accuracy in real-time. In this study, we show and test a new electronic device (ZooLog KLP), which was developed to detect WCR in the field. The ZooLog KLP consists of a trapping element that attracts insects with its color and species-specific sex pheromone. The other part is an opto-electronic sensor-ring which detects the specimens when they fall into the trap. At detection, the time of catch is recorded and sent to a web interface. In this study, we followed WCR flight patterns for six weeks in two locations, using ZooLog KLP probes. We investigated sensor precision by comparing the number of catches to the number of detections. The tool reached high accuracy (95.84%) in recording WCR. We found a peak in flight activity in August and a bimodal daily pattern. This method may be beneficial in detecting the WCR during their activity, and this new device may serve as a prototype for real-time monitoring systems and improve the management of this pest.

Entomopathogenic Nematodes: A Green Strategy For Management of Insect Pests of Crops

Chapter

Nov 2019

A piece of brief information on EPNs

Compatibility of Heterorhabditis amazonensis MC01 (Nematoda: rhabditida) with fertilizers and soil conditioners

Article

Full-text available

Nov 2019

Entomopathogenic nematodes are natural enemies of insect pests present in the soil; however, the intensive use of agricultural inputs can affect the action of these organisms. The objective of this study was to evaluate the effects of exposure of the nematode Heterorhabditis amazonensis MC01 to soil fertilizers containing different active ingredient, verifying their influence in the viability, infectivity and nematode production in Tenebrio molitor L. larvae. Nine products were tested, including fertilizers and soil conditioners, using the adapted IOBC/WPRS protocol. The infective juveniles were exposed to the highest concentration recommended by the manufacturer of each product for a period of 48 h. After this period, the viability, infectivity and production were evaluated and the values of mortality, infectivity reduction, production reduction and insecticide effect were obtained in order to classify the products according to IOBC criteria. In this way, the nematode H. amazonensis MC01 was compatible with most of the products under the tested conditions, so could be present in the soil at the same time. However, the product Nutriterge® Formula 3 was considered slightly harmful and Nem out® considered harmful. However, further field tests should be performed with these products to prove the deleterious effect on the nematode tested.

Pheromone extracts act as boosters for entomopathogenic nematodes efficacy

Article

Apr 2019

Inconsistency in entomopathogenic nematode (EPN) efficacy is still one of the biggest challenges for the wider adoption of EPNs as biocontrol agents. Previous studies demonstrated that extracts from EPN-infected hosts enhance dispersal and efficacy, two key factors in success of EPNs. Some active components in the insect host cadavers responsible for dispersal, ascarosides, have been identified as nematode pheromones. We hypothesized that pheromone extracts increase dispersal of EPN infective juveniles (IJs) leading to increased efficacy. First, we determined whether pheromone extracts improved IJ movement/dispersal in soil columns baited with Tenebrio molitor larvae. We found that pheromone extracts induced higher numbers of Steinernema carpocapsae and Steinernema feltiae IJs to move towards T. molitor larvae in the bottom of the column compared to IJs treated with infected cadaver macerate and water, positive and negative controls, respectively. Furthermore, the number of S. carpocapsae IJs that invaded T. molitor larvae was higher for the pheromone extract treatment than the controls. S. feltiae IJs that were pretreated with pheromone extracts and macerate (positive control) infected T. molitor at the same rate but invasion was superior to IJs that were treated with water. Consistent with the soil column tests, both S. carpocapsae and S. feltiae IJs treated with pheromone extracts performed better in killing larvae of two economically important insect larvae, pecan weevil, Curculio caryae, and black soldier fly, Hermetia illucens, in greenhouse tests compared to IJs treated with water. We demonstrated pheromone-mediated behavioral manipulation of a biological control agent to enhance pest control potential. Conceivably, nematodes can be exposed to efficacy-enhancing pheromones prior to field application.

Effect of chlorpyrifos on survival and virulence of native entomopathogenic nematode

Article

Jun 2018

Combining compatible insecticides with entomopathogenic nematodes may constitute an effective alternative to conventional chemical control as efficient tool for pest and disease control in areca nut and coconut. Hence, in vitro a compatibility test was conducted to evaluate the effect of chlorpyrifos which is widely used against root grubs on native entomopathogenic nematode isolate, Steinernema carpocapsae (CPCRI-SC1). Results indicated that different concentrations of chorpyrifos significantly influenced the infective juveniles (IJs) mortality at 96 h of exposure. The maximum percent mortality of infective juveniles was recorded at higher concentration of insecticide 3200 ppm (31.5%) followed by 1600ppm (26.2%), whereas minimum percent mortality (18.2%) was recorded at lower concentration (200 ppm) followed by 400 ppm (21.3%) at 96 h of exposure. Increase in the mortality of IJs was noticed with increase in concentration (200-3200 ppm) along with their exposure periods (24-96 h). No significant difference was recorded in mass production and infectivity of IJs exposed to different concentrations of insecticide on third instar G. mellonella. The results showed tolerance between native EPN isolate S. carpocapsae and chlorpyrifos insecticide at lower concentration as it does not affect the biological parameters of the native EPN isolate.

Efficacy of Two Entomopathogenic Fungi, Metarhizium brunneum, Strain F52 Alone and Combined with Paranosema locustae against the Migratory Grasshopper, Melanoplus sanguinipes, under Laboratory and Greenhouse Conditions

Article

Full-text available

Mar 2019

Grasshopper outbreaks cause significant damage to crops and grasslands in US. Chemical control is widely used to suppress these pests but it reduces environmental quality. Biological control of insect pests is an alternative way to reduce the use of chemical insecticides. In this context, two entomopathogenic fungi, Metarhizium brunneum strain F52 and Paranosema locustae were evaluated as control agents for the pest migratory grasshopper Melanoplus sanguinipes under laboratory and greenhouse conditions. Third-instar grasshoppers, reared in the laboratory, were exposed up to fourteen days to wheat bran treated with different concentrations of each of the fungi alone or the two pathogens combined. In the greenhouse, nymphs were placed individually in cages where they were able to increase their body temperatures by basking in the sun in an attempt to inhibit the fungal infection, and treated with each pathogen alone or in combination. Mortality was recorded daily and presence of fungal outgrowth in cadavers was confirmed by recording fungal mycosis for two weeks’ post-treatment (PT). For combination treatment, the nature of the pathogen interaction (synergistic, additive, or antagonistic effects) was also determined. In laboratory conditions, all treatments except P. locustae alone resulted in grasshopper mortality. The application of the pathogen combinations caused 75% and 77%, mortality for lower and higher concentrations, respectively than each of the pathogens alone. We infer a synergistic effect occurred between the two agents. In greenhouse conditions, the highest mortalities were recorded in combination fungal treatments with a M. brunneum dose (60% mortality) and with a combination of the two pathogens in which M. brunneum was applied at high rate (50%) two weeks after application. This latter combination also exhibited a synergistic effect. Exposure to the P. locustae treatment did not lead to mortality until day 14 PT. We infer that these pathogens are promising for developing a biopesticide formulation for rangeland pest grasshopper management.

Combined Application of Entomopathogenic Nematodes and Insecticides in the Control of Leaf-Miner Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) on Tomato

Article

Full-text available

Nov 2018

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.

The potential of entomopathogens in biological control of white grubs

Article

Full-text available

Nov 2018

White grubs are highly polyphagous and most destructive soil pests inflicting damage to awide variety of crops. In India, more than 1000 species of white grubs are known of whichover 40 species attack wide range of plants. White grubs are naturally infected by variousentomopathogens which include fungi, bacteria and nematodes. Entomopathogenic fungioffer great potential and members of generaBeauveriaandMetarhiziumare widely usedagainst white grubs. Several commercial products of entomopathogenic fungi like Bio Green,ORY-X, Grub X 10G, Betel, Biotrol FMA and Meta-Guard have been developed for the controlof white grubs. In India, good control of white grubs in paddy, ginger and sugarcane hasbeen achieved with different entomofungi. Among EPNs,Heterorhabditis bacteriophorais moderately effective againstPopillia japonicaandRhizotrogus majalis.H. indicaandH. bacteriophoraare effective against potato white grubs in India.Paenibacillus popilliaecause milky disease inP. japonicagrubs. The bacterium is pathogenic toHolotrichiaconsanguinea,H. serrataandLeucopholis lepidophora. In north-western Himalaya,B. cereusis highly toxic to the grubs ofH. seticollisandAnomala dimidiata.

The potential of entomopathogens in biological control of white grubs

Article

Full-text available

Oct 2018
INT J PEST MANAGE

White grubs are highly polyphagous and most destructive soil pests inflicting damage to a wide variety of crops. In India, more than 1000 species of white grubs are known of which over 40 species attack wide range of plants. White grubs are naturally infected by various entomopathogens which include fungi, bacteria and nematodes. Entomopathogenic fungi offer great potential and members of genera Beauveria and Metarhizium are widely used against white grubs. Several commercial products of entomopathogenic fungi like Bio Green, ORY-X, Grub X 10G, Betel, Biotrol FMA and Meta-Guard have been developed for the control of white grubs. In India, good control of white grubs in paddy, ginger and sugarcane has been achieved with different entomofungi. Among EPNs, Heterorhabditis bacteriophora is moderately effective against Popillia japonica and Rhizotrogus majalis. H. indica and H. bacteriophora are effective against potato white grubs in India. Paenibacillus popilliae cause milky disease in P. japonica grubs. The bacterium is pathogenic to Holotrichia consanguinea, H. serrata and Leucopholis lepidophora. In north-western Himalaya, B. cereus is highly toxic to the grubs of H. seticollis and Anomala dimidiata.

The saprophytic fungus Fusarium solani increases the insecticidal efficacy of the entomopathogenic nematode Steinernema diaprepesi

Article

Oct 2018

In two field surveys, high proportions of Galleria mellonella L. (Lepidoptera: Pyralidae) sentinel larval cadavers were infected by Fusarium solani without evidence of concomitant entomopathogenic nematode (EPN) or entomopathogenic fungus (EPF) reproduction. Because F. solani is not considered entomopathogenic, the survey suggested the possibility that F. solani competes with EPNs. We tested the hypotheses that F. solani attracts the EPN, Steinernema diaprepesi, to facilitate infection of Diaprepes root weevils (Diaprepes abbreviatus L.) and thereafter competes with the nematode in the insect cadaver. In two-choice olfactometer assays where one side was treated with F. solani mycelia and conidia, juvenile S. diaprepesi were attracted to the fungus, in either raw soil, or in autoclaved soil in the presence or absence of insects. However, this attraction was attenuated as the habitat became more complex, by using raw soil in combination with insect larvae. Fusarium oxysporum did not recruit the nematode. When soil microcosms were tested with F. solani conidia and S. diaprepesi, the concomitant infection increased the mortality of the insect (P = 0.02) to 83%, compared to 58% and 0% mortality when nematodes or fungi were individually applied, respectively. Concomitant inoculation also increased the number of cadavers that supported nematode reproduction and increased the population density of fungus in soil. The number of IJs entering the host insect was not affected by F. solani. These results support the possibility that F. solani can facilitate the insecticidal efficiency of S. diaprepesi in order to exploit the resources in the cadaver.

Fipronil enhanced natural occurrence of Fusarium solani (Hypocreales: Nectriaceae) on building infesting termite Heterotermes indicola Wasmann (Blattodea: Rhinotermitidae)

Article

Full-text available

Feb 2018
J Asia Pac Entomol

The Southeast Asian subterranean termite, Heterotermes indicola Wasmann (Blattodea; Rhinotermitidae), is recognized as a building infesting lower termite species in urban environment. The extensive use of chemical termiticides against aerial mud tubes and underground nests of H. indicola beneath the buildings could not suppress its infestation; however, it enhanced the environmental contamination and insecticide resistance. In the present study, we tried to control termites using naturally occurring entomopathogenic fungi Fusarium solani (Mart.) Sacc., along with sublethal concentrations of termiticide fipronil in no-choice feeding pathogenecity bioassay for 20 days. Termite mortality after 20 days of continuous exposure to highest fungal treatment 1 × 10⁹ conidia/mL was 10% exclusively, whereas 100% mortality was calculated just after 16 days of concurrently exposure to 5 ppm of fipronil and highest rate of fungus 1 × 10⁹ conidia/mL. These results indicated that insecticidal stress declined the immune response of termites and reduced the repellency of termites against fungal conidia by breaching the primary defense mechanism (allogrooming). This co-application of F. solani at suitable sublethal concentrations of fipronil showed the promising potential against termites that may reduce the selection pressure of pesticides and resistance risk by targeted pests, but further investigations are necessary for developing field trials.

Entomopathogenic nematodes and their mutualistic bacteria: Their ecology and application as microbial control agents

Article

Full-text available

Dec 2017

Entomopathogenic nematodes (EPNs) belonging to the families heterorhabditidae (genus Heterorhabditis) and steinernematidae (genus Steinernema) are mutualistically associated with bacteria in the family Enterobacteriaceae (Photorhabdus spp. for Heterorhabditis and Xenorhabdus spp. for Steinernema). At present, there are 100 Steinernema and 17 Heterorhabditis species and 20 Xenorhabdus and 4 Photorhabdus species. In general, each EPN species has its own bacterial species, but a given bacterial species may be associated with more than one EPN species. The EPNs' natural habitat is the soil where the nematode-bacterium complex infects many different insect species killing them within 48 h. EPNs have been isolated from many different islands and from all continents except antarctica. Because EPNs and their associated bacteria are safe to humans, other vertebrates, and plants, can effectively kill soil insect pests in a short time, serve as an alternative to chemical pesticides, are easily massed produced in vivo and in vitro, and do not require registration in many countries, a number of EPN species have been produced commercially to target soil and plant-boring pests in high value crops. Moreover, the associated bacteria produce antibiotics and other compounds that have potential to be used against human, veterinary, and plant pathogens.

Combining the botanical insecticides NSK extract, NeemAzal T 5%, Neemix 4.5% and the entomopathogenic nematode Steinernema feltiae Cross N 33 to control the peach fruit fly, Bactrocera zonata (Saunders)

Article

Full-text available

Feb 2018

Mahmoud Farag Mahmoud

Botanical insecticides based on azadirachtin and the entomopathogenic nematode Steinernema feltiae were evaluated for their control of the peach fruit fly, Bactrocera zonata . Laboratory bioassays determined the potential of combinations between the biological control agent S. feltiae and the botanical insecticides NSK, NeemAzal T 5%, Neemix 4.5% against 3rd instar larvae of B. zonata . Of 25 treatment combinations between azadirachtin from NSK extract and S. feltiae , 18 gave synergistic responses, 4 were additive, none antagonistic and 3 without any response. The same number of combinations with NeemAzal T 5% showed 19 synergistic responses, 1 additive, none antagonistic and 5 without any response. Combinations of Neemix 4.5% and S. feltiae showed 11 synergistic responses, 5 additive, 3 antagonistic and 6 without any response. The combined use of botanical insecticides based on azadirachtin, especially NSK extract and NeemAzal T 5%, with the entomopathogenic nematode S. feltiae may offer an integrated approach to increase the efficacy of control of the peach fruit fly, B. zonata , by entomopathogenic nematodes.

An innovative strategy for control of the chestnut weevil Curculio elephas (Coleoptera: Curculionidae) using Metarhizium brunneum

Article

Dec 2017
CROP PROT

The chestnut weevil (Curculio elephas) is a major pest of chestnut. Female weevils oviposit in the fruit and emergent larvae eat the kernel, making the nut unmarketable. In Turkey, the fruit is gathered into piles called gomu and allowed to ripen over a 1–2 month period. Late instars emerge from infested nuts to pupate in the soil underlying the gomu. Since the pest is concentrated, the opportunity exists for targeted control with biological control agents such as entomopathogenic fungi (EPF) and nematodes (EPN). The efficacy of the EPF Metarhizium brunneum strains ARSEF 4556 and V275 used alone and in combination with the EPN Heterorhabditis bacteriophora on the mortality of last instar chestnut weevil was assessed. Both M. brunneum ARSEF 4556 and V275 were highly virulent causing 86% and 94% mortality, respectively. Although H. bacteriophora killed the larvae (68% mortality) more quickly, the fungal strains were more efficacious 12 days post-inoculation. Application of ARSEF 4556 and V275 as a top dressing (spreading the fungus uniformly over the soil surface) in simulated gomu resulted in 78% and 80% larval mortality in laboratory pot tests and 83% and 70% mortality in outdoor trials, respectively. Premix applications (mixing the fungus in the top few centimeters of soil) of ARSEF 4556 and V275 resulted in 83% and 85% larval mortality indoors, respectively, yet outdoor trials caused >80% larval mortality. These EPF strains were also evaluated against larvae of the chestnut tortrix, Cydia splendana, which also feeds on nut kernels, and emerges at the same time as the chestnut weevil larvae to pupate in the soil. Both ARSEF and V275 caused 96.6% mortality inlast instar C. splendana. In contrast, the most virulent EPN (Steinernema feltiae) caused only 80% mortality. Co-application of this nematode with M. brunneum resulted in 100% mortality with the interactions being additive.

Book: Current Trends in Parasitology Edited: Veena Tandon,Arun K Yadab and Bishnupada Ray Paper: Studies on infection and cross-infection of microsporidian spores of mulberry, tasar, eri and muga silkworm on economic parameters of silk to mulberry silkworm, Bombyx mori L. Satadal Chakrabarti and Buddhadeb Manna, Department of Zoology, University of Calcutta, Kolkata

Book

Full-text available

Nov 2009

Satadal Chakrabarty

Pebrine is a deadly disease of mulberry silkworm, Bombyx mori L., caused by the pathogen Nosema bombycis (Microsporidia: Nosematidae). Economic parameters of silk viz., cocoon weight, shell weight, length and circumference of cocoon, shell percentage and filament length of cocoon during microsporidian infection and cross-infection with Nosema bombycis and N. mylitta in mulberry silkworm, Bomyx mori L. in three different seasons are studied. Generally all the economic characters of silks are deteriorated in infected and cross-infected cocoons over healthy control. The study indicates that economic parameters of silk are directly related to the microsporidian infection and cross-infection in mulberry silkworm. Keywords Bombyx mori; Cross-infection; Economic parameters; Microsporidian; Nosema bombycis; Silk Ratio percentage

Book title: Current Trends in Parasitology : Paper: STUDIES ON CROSS-INFECTION OF MICROSPORIDIAN SPORES OF MULBERRY,ERI AND TASAR SILKWORM TO MUGA SILKWORM,ANTHERAEA ASSAMENSIS Ww. AND A NEW APPROACH FOR MANAGEMENT OF PEBRINE DISEASE IN MUGA SILKWORM IN ASSAM AND WEST BENGAL,INDIA

Book

Full-text available

Nov 2009

Satadal Chakrabarty

Searching for Better Methodologies for Successful Control of Termites Using Entomopathogenic Nematodes

Chapter

Full-text available

Aug 2017

Compatibility and interaction with agrochemicals and biocontrol agents

Article

Jan 2005

In vitro interaction of Metarhizium anisopliae Ma9236 and Beauveria bassiana Bb9205 with Heterorhabditis bacteriophora HNI0100 for the control of Plutella xylostella

Article

Full-text available

Dec 2016

The diamondback moth (Plutella xylostella) is a major pest of broccoli crops in Colombia. To control P. xylostella, we evaluated the interaction of Beauveria bassiana Bb9205 and Metarhizium anisopliae Ma9236 with Heterorhabditis bacteriophora HNI0100 and its bacterial symbiont Photorhabdus luminescens HNI0100. We used antagonism and disk diffusion assays with fungal extracts to test the interaction between symbiotic bacterium and fungi. P. luminescens inhibited the growth of B. bassiana and M. anisopliae up to 40% by the secretion of secondary metabolites, whereas fungal extracts did not inhibit P. luminescens; this explains the in vivo interactions of these biological control agents. To test the interaction between fungi and nematodes, we first inoculated the fungi followed by the nematodes on different days (0, 2, 4, and 6). We identified the type of interaction using the formula by Nishimatsu and Jackson (J Econ Entomol 91:410–418, 1998) and established that on days 0, 2 and 4 there was an antagonistic interaction, while a synergistic interaction occurred on day 6. Therefore, the use of the interaction between H. bacteriophora HNI0100 with M. anisopliae Ma9236 and B. bassiana Bb9205 is an innovative alternative for the control of P. xylostella.

Integrated resistance management for acaricide use on Varroa destructor

Article

Full-text available

Dec 2023

Phil J. Lester

The global beekeeping industry faces an escalating challenge in the form of Varroa destructor. Synthetic chemicals serve as a cornerstone for varroa management, although they face a major challenge in the form of acaricide resistance. Here, I examine acaricide resistance in varroa under the framework of Insecticide Resistance Management (IRM). I assess the potential of diverse IRM strategies, such as pesticide rotation and mixtures, refuge utilization, synergists and the integration of non-persistent chemicals. The peculiar life history of varroa, characterized by its incestuous breeding system, challenges conventional IRM strategies. There is little published evidence that pesticide rotation is beneficial for resistance management in varroa, with several studies showing resistance is maintained despite rotation. Fitness costs associated with pesticide resistance are often an essential component for IRM strategies, but there are no current data from varroa demonstrating such specific fitness costs (e.g., a reduced relative oviposition rate) associated with resistance. The single published experimental study directly examining relative fitness found that here was little or no reproductive fitness cost associated with pyrethroid resistance. More work is needed on fitness effects of the key acaricides, which would better guide the use of rotation and refuge strategies. A key prospect for future work that has been identified through simulation modeling is offered by pesticide mixtures and the role of synergists to elevate acaricide efficacy. Additional tools for varroa IRM include 'soft' acaricides, including oxalic acid, and biopesticides such as dsRNA. In light of the widespread prevalence of acaricide resistance and an increasing varroa problem, there is an urgent need for nuanced, data-driven varroa IRM strategies. CITATION Lester PJ (2023) Integrated resistance management for acaricide use on Varroa destructor.

Entomopathogenic Nematodes

Chapter

Jan 2021

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.

Field Application Techniques for Control of Insect Pests

Chapter

Apr 2021

The field application of entomopathogenic nematodes for control of insect pests requires knowledge of the occurrence, species diversity, biology, ecology, distribution and insect host range of native EPN species. Commercially produced EPN species are applied in the crop fields as safe and effective biocontrol agents. Formulation helps in the safe storing and transporting of the mass-produced EPNs. The components and effectiveness of various formulations, survivability tests and infectivity tests are described. Application efficacy depends on the selection of the right nematode species to match against the target insect and application should be started as soon as the insect pest population is observed to cause crop damage. Soil application procedures are explained.

Entomopathogenic Nematodes and Insect Pest Management

Chapter

Oct 2001

Effects of entomopathogenic nematodes and/or fungus on the red palm weevil, Rhynchophorus ferrugineus (Curculionidae: Coleoptera)

Article

Jun 2020

The invasive red palm weevil (RPW) ( Rhynchophorus ferrugineus ) (Coleoptera: Curculionidae) is one of the most destructive palm pests in the world. More options are needed for its management, including optimised use of microbial entomopathogens (EP). The sub-lethal effects of an entomopathogenic fungus (EPF) Beauveria bassiana (isolate WG-11) (Ascomycota: Hypocreales) (at 1 × 10 ⁴ spores ml ⁻¹ ) and two entomopathogenic nematode (EPN) species, Heterorhabditis bacteriophora (at 100 infective juveniles (IJ) ml ⁻¹ ) and Steinernema carpocapsae (at 50 IJ ml ⁻¹ ) were evaluated in various combinations against laboratory-reared 3rd, 5th and 8th instar larvae of RPW in bioassays. Individual and combined effects of both EP were observed after the pre-application of B. bassiana fungus at 0-, 1- and 2-week intervals. Combined treatments were tested for antagonistic, additive and synergistic effects. Additive and synergistic effects were observed in B. bassiana / S. carpocapsae and in B. bassiana / H. bacteriophora combined treatments. Early instar larvae of RPW were more susceptible than older instars. Sole and combined EP treatments decreased pupation, subsequent emergence of RPW adults and hatching. Sub-lethal effects of EP were observed in R. ferrugineus following application at the above-mentioned rates to 3rd, 5th and 8th instar larvae, including reduced larval weights, increased larval, pre-pupal and pupal durations, reduced adult weights and life spans. Simultaneous combined applications of B. bassiana / S. carpocapsae and B. bassiana / H. bacteriophora at the above-mentioned rates against last instar (9th) larvae of R. ferrugineus reduced food consumption, frass production and affected weight gains.

COMPATIBILITY OF ENTOMOPATHOGENIC NEMATODES, Heterorhabditis bacteriophora Poinar AND Steinernema carpocapsae Weiser WITH SOME CHEMICAL AND BIOPESTICIDES

Article

Full-text available

Dec 2018

Effect of the nematicides (abamectin, fenamiphos and oxamyl) as well as the biopesticides (Bio-arc, Bio-zeid and Nemex) on viability and infectivity of infective juveniles (IJs) of the two entomopathogenic nematodes (EPNs) viz., Heterorhabditis bacteriophora (HP88 strain) and Steinernema carpocapsae (All strains) were assessed under laboratory conditions against the six instar larvae of Galleria mellonella L. Results indicated that one day after treatment, the tested pesticides reduced the viability of IJs by 9.83 to 23.00% depending on the pesticide and nematode species. After two days, IJs mortality was obviously increased to reach 23.00, 37.50 and 38.33% with the chemical pesticides abamectin, fenamiphos and oxamyl, respectively at the recommended doses. At half recommended doses, IJs mortality reached 14.50, 20.16 and 29.00%, respectively for the same pesticides. Whereas, the parallel values in abamectin, fenamiphos, and oxamyl at the seventh day were 42.83, 63.16; 74.17, 91.83 and 74.00, 86.16% at the half and recommended dose, respectively, after the seventh day, fenamiphos was the most toxic among the tested chemical pesticides followed by oxamyl and abamectin.The biopesticides Bio-arc (Bacillus megaterium), Bio-zeid (Trichoderma album) and Nemex (Serratia marcescens) on IJs mortality of H. bacteriophora and S. carpocapsae were less toxic as compared to chemical pesticide. After seven days of treatment, at the recommended and half recommended doses, IJs mortality reached to 63.00, 43.66; 45.49, 41.66 and 42.83, 34.17% with Nemex, Bio-arc and Bio-zeid, respectively. Nemex was the most toxic among the tested biopesticides followed by Bio-arc and Bio-zeid. Results indicated that the pesticides screened for their compatibility with H. bacteriophora and S. carpocapsae in controlling the 6 th instar larvae of G. mellonella showed an additive or antagonistic reactions. No evidence of synergy was observed. The additive effect took place for most of the tested treatments, while the antagonistic effect was detected in combinations of H. bacteriophora with oxamyl, S. carpocapsae with fenamiphos and both of S. carpocapsae and H. bacteriophora with Nemex. Incompatibility in these cases can be managed by choosing an appropriate time-intervals between nematode and pesticide applications.

Entomopathogen and Synthetic Chemical Insecticide: Synergist and Antagonist

Chapter

Sep 2019

Arash Zibaee

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.

Investigation on bio-efficacy, LD 50 and LT 50 of Steinernema carpocapsae against Spodoptera litura

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Jan 2016

Bio-efficacy of S. carpocapsae was studied against Tobacco caterpillar under laboratory conditions. The per cent mortality of insect larvae was recorded after every 12 hrs up to 168 hrs at different inoculum levels viz., 100, 200, 300, 400 and 500 IJs per Petri plate (5 larvae/Petri plate). The experimental results revealed that maximum (100.00) per cent mortality of S. litura was recorded within 72 hrs of exposure at an inoculum level of 500 IJs of S. carpocapsae. While, minimum 50 per cent mortality of S. litura was observed after 72 hrs at 100 IJs per Petri plate. After 132 hrs 100 per cent mortality of S. litura was recorded at all inoculum levels viz., 500, 400, 300, 200 and 100 IJs per Petri plate, respectively. The LD 50 values after 12, 24, 36, 48, 60, 72, 84 and 96 hrs of exposure were 959.4, 469.9, 325.1, 219.8, 152.1, 77.8, 49.09 and 16.26 IJs per Petri plate (5 larvae/ Petri plate), respectively and the LT 50 values recorded were 68.2, 50.23, 40.83, 31.7 and 23.04 hrs, at inoculum levels of 100, 200, 300, 400 and 500 IJs per Petri plate, respectively. S. litura was found highly susceptible to S. carpocapsae and the mortality of insect larvae further increased with an increase in the inoculum levels and period of exposure.

Compatibility of chemical insecticides and entomopathogenic fungi for control of soybean defoliating pest, Rachiplusia nu

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Oct 2017
Rev Argent Microbiol

Rachiplusia nu (Guenée) (Lepidoptera: Noctuidae) is one of the major lepidopteran pests defoliating soybeans (Glycine max Merrill) in Argentina. The combined use of chemical insecticides and entomopathogenic fungi is a promising pest-control option to minimize adverse chemical effects. In this work, we evaluated the interactions between five insecticides-two being considered biorational-and five fungal entomopathogenic strains under laboratory conditions in order to determine the possible usefulness of combinations of these agents against R. nu. The insecticides were tested for compatibility at four doses by in vitro bioassay and for the lethality of R. nu by inoculations at three doses. Fungal strains were applied at 1×10(8), 1×10(6), and 1×10(4)conidia/ml. The combinations of those insecticides with Beauveria bassiana (LPSc 1067, LPSc 1082, LPSc 1098), Metarhizium anisopliae (LPSc 907), and Metarhizium robertsii (LPSc 963) caused higher R. nu-larval mortalities than any of the individual agents alone. We observed significant differences in the in vitro conidial viability, vegetative growth, and conidia production of the five strains of entomopathogenic fungi exposed to different doses of the chemical insecticides. The combination gamma-cyhalothrin-LPSc-1067 caused the highest percent mortality of R. nu larvae, with synergism occurring between the two agents at 50% and 25% of the maximum field doses.

Synergistic effect of entomopathogenic nematodes and thiamethoxam in controlling Bradysia odoriphaga Yang and Zhang (Diptera: Sciaridae)

Article

May 2017

Six entomopathogenic nematode species (EPNs) (Heterorhabditis bacteriophora H06 (H06), Steinernema carpocapsae NC116 (NC116), Steinernema carpocapsae All (All), Steinernema longicaudum X-7 (X-7), Steinernema feltiae SF-SN (Sf) and Heterorhabditis indica LN2 (LN2) were tested for virulence against 3rd instar Bradysia odoriphaga, and their interactions with thiamethoxam against 3rd instar B. odoriphaga under laboratory and greenhouse conditions were also evaluated. S. feltiae SF-SN, which is the most virulent, was selected to evaluate the synergism effects with thiamethoxam at different concentrations under laboratory conditions. S. feltiae SF-SN and thiamethoxam were either applied alone or in combination, and the combined application manner was evaluated in the greenhouse. Under laboratory conditions, a synergistic effect was found between six EPNs and thiamethoxam. The combination effects of Sf, All and LN2 species caused significantly higher mortality than the other three treatments (X-7, H06 and NC116). Furthermore, the combination of Sf and All species led to a significantly higher control effect than LN2 in greenhouse tests. In further greenhouse tests, the combination effect of Sf (0.75 billion IJs/ha) + thiamethoxam (1.0 kg a.i./ha) applied twice (28 day intervals) was significantly higher than a single treatment of Sf + thiamethoxam at twice the dosage. Compared to the single thiamethoxam application, the combination effects of Sf and thiamethoxam had the highest value at over 90% of the control effects for up to 6 weeks. Therefore, the integrated technique of the synergism of S. feltiae SF-SN species and thiamethoxam to control B. odoriphaga could be useful for integrated pest management in the future.

Scientific Opinion addressing the state of the science on risk assessment of plant protection products for in-soil organisms

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Full-text available

Feb 2017

Following a request from EFSA, the Panel on Plant Protection Products and their Residues developed an opinion on the science behind the risk assessment of plant protection products for in-soil organisms. The current risk assessment scheme is reviewed, taking into account new regulatory frameworks and scientific developments. Proposals are made for specific protection goals for in-soil organisms being key drivers for relevant ecosystem services in agricultural landscapes such as nutrient cycling, soil structure, pest control and biodiversity. Considering the time-scales and biological processes related to the dispersal of the majority of in-soil organisms compared to terrestrial non-target arthropods living above soil, the Panel proposes that in-soil environmental risk assessments are made at in- and off-field scale considering field boundary levels. A new testing strategy which takes into account the relevant exposure routes for in-soil organisms and the potential direct and indirect effects is proposed. In order to address species recovery and long-term impacts of PPPs, the use of population models is also proposed.

Interaction of Insecticides, Entomopathogenic Nematodes, and Larvae of the Western Corn Root worm (Coleoptera: Chrysomelidae)

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