Figure 2 - uploaded by Kent Daane
Content may be subject to copyright.
Mummified psyllids showing the now transparent mummy (exoskeleton) enclosing (a) a white, newly formed Psyllaephagus bliteus pupa and (b) a better-developed P. bliteus pupa covered by the black pupal sheath.
Source publication
Abstract Psyllaephagus bliteus was imported from Australia in 1999 and released in California in 2000 as part of a classical biological control program targeting the red-gum lerp psyllid, Glycaspis brimblecombei, which in California feeds mainly on red gum, Eucalyptus camaldulensis Dehnh. Psyllaephagus bliteus is an internal parasitoid that delays...
Contexts in source publication
Context 1
... psyllid mummy forms a potential second line of defence for the P. bliteus pupa. When the parasitised host dies, its exoskeleton forms the easily recognised mummy (Fig. 2). By this time, the P. bliteus has completely consumed the psyl- lid nymph and has nearly finished its larval development. The mummified exoskeleton of the dead psyllid becomes transpar- ent and the white larva of P. bliteus can be seen (Fig. 2a), typically with its head at the posterior end of the mummified psyllid. When the P. ...
Context 2
... the P. bliteus pupa. When the parasitised host dies, its exoskeleton forms the easily recognised mummy (Fig. 2). By this time, the P. bliteus has completely consumed the psyl- lid nymph and has nearly finished its larval development. The mummified exoskeleton of the dead psyllid becomes transpar- ent and the white larva of P. bliteus can be seen (Fig. 2a), typically with its head at the posterior end of the mummified psyllid. When the P. bliteus's final larval stage voids the meco- nium, the flat, oval-shaped fecal pellets are typically found at the anterior end of the psyllid mummy, since the anus of the white larva is most often orientated in that direction. This observation is ...
Context 3
... the mummified psyllid, the white pupa is gradually covered by the black pupal sheath (Fig. 2b), giving the mis- leading impression of a darkly melanised exoskeleton. The excised P. bliteus pupa shows the dorsal (Fig. 3a) and ventral (Fig. 3b) views of the fully developed pupal sheath. The pupal sheath of P. bliteus fits tightly and is well developed based on the few available descriptions of the pupal sheaths of other parasitoid ...
Similar publications
In 1992 a parasitoid native to Australia was introduced into California in a biological
control program directed against the blue gum psyllid from Australia. Interviews with
baby blue gum eucalyptus growers indicate that this program has had a benefit-cost
ratio ranging from at least 9:1 to 24:1, based solely on the reduction of insecticide
treatme...
Citations
... Psyllaephagus bliteus modifies the physiology of G. brimblecombei nymphs, increasing carbohydrate and protein excretion for its self-protection. Parasitoid development begins when the G. brimblecombei nymph reaches the fifth instar (Sullivan et al. 2006). ...
The potential of the parasitoid Psyllaephagus bliteus Riek for the biological control of the eucalyptus pest Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae) nymphs is high. This research sought to analyze the courtship, male competition, and mating behavior of P. bliteus at the proportions of 1:1 and 2:1 males to female in a Petri dish (5 cm diameter), and to describe the ovary histology of virgin and mated females of this parasitoid. At 1:1, males touch the antennae and thorax-abdomen of females during courtship, but females avoid mate attempts before they are 48 h old. At 2:1, the competition between male parasitoids inhibits mating. The histology of ovaries of virgin and mated P. bliteus females is similar, with two well-defined germarium and vitellarium regions, with oocytes at different developmental stages, including mature ones rich in yolk and with eggshell. A clearer understanding of the reproductive behavior and histology of P. bliteus aids in the use of this parasitoid for the biological control of G. brimblecombei.
... The nymphs of G. brimblecombei secrete a conical covering (lerp) composed of solidified honeydew (Sharma et al., 2013), which protects them until they reach adulthood (Sullivan et al., 2006). The lerp expands as nymphs grow and lerp size can therefore be easily used to characterize changes between instars (Stivanelli et al., 2009). ...
The red gum lerp psyllid, Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae), is considered one of the most important pests of Eucalyptus worldwide. Since its detection in Brazil in 2003, the insect has caused defoliation in forests, twig dieback and sooty mold. Several types of management were evaluated, but few studies focused on the search for resistant Eucalyptus species and hybrid clones. The present study aimed to assess the biological performance of G. brimblecombei on E. camaldulensis, E. urophylla, and E. grandis and on the hybrids E. grandis x E. camaldulensis (1277 and 3025), E. urophylla x E. camaldulensis (VM-01), and E. urophylla x E. grandis (C-219, H-13, GG-100 and I-144), in order to determine resistance mechanisms. Under laboratory conditions (T= 26 ± 2°C; RH= 60 ± 10%; photoperiod= 12 h), psyllids on each of the ten Eucalyptus genotypes were evaluated daily until adult emergence. Genotypes C-219 and H-13 (E. urophylla x E. grandis) exhibited high levels of antibiosis and/or antixenosis (nonpreference) resistance to G. brimblecombei, drastically reducing nymph viability (mortality > 80%). In turn, genotypes 3025 (E. grandis x E. camaldulensis) and E. camaldulensis were highly susceptible to the biological development of red gum lerp psyllids. Our results may contribute to genetic improvement programs aimed at obtain G. brimblecombei resistant Eucalyptus genotypes.
... The present work demonstrated that C. externa larvae are able to prey on psyllid nymphs, even when these were under the lerp, a solidified honeydew and wax cover secreted by the nymphs. Several authors have mentioned that the lerp protects the nymphs from predator and parasitoid attacks (Hollis, 2004;Sullivan, Daane, Sime, & Andrews, 2006). However, in the predatory capacity assay described here, it was observed that when the lerp was recently built and therefore soft, C. externa larvae pierced it with its mouthparts to consume the nymph, while when 94.75 ± 12.25a a Relationship between females that oviposited viable eggs during the assay and total number of females. ...
The green lacewing Chrysoperla externa is a widespread species in the Neotropical region that occurs in different habitats. Its presence in Eucalyptus plantations infested with Glycaspis brimblecombei (Hemiptera: Aphalaridae) and Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae) suggests that this lacewing might feed on one or both exotic pest species. In order to evaluate C. externa as a potential biocontrol agent of the eucalyptus pests, the prey consumption, development, survival and reproduction of the predator were evaluated under laboratory conditions. C. externa larvae consumed nymphs of both pest species. Developmental time and reproduction parameters of C. externa fed G. brimblecombei were similar to those obtained with the factitious prey Sitotroga cerealella. When fed on T. peregrinus, C. externa showed a delay in its developmental time and the emerged adults were malformed. The results of this study suggest that the green lacewing is a good candidate to be used in augmentative or conservative biological control programmes against G. brimblecombei. Further research is necessary to analyse the potential of this predator as a biocontrol agent under field conditions.
... The exoskeleton of the dead parasitized hosts forms an easily recognized mummy, and the psyllid nymph is completely consumed as the parasitoid nearly finishes development. The white P. bliteus larva can be seen throughout the mummified exoskeleton of G. brimblecombei, which becomes transparent (Sullivan et al., 2006). P. bliteus was accidentally introduced into Brazil and was first reported soon after its host in 2003 (Berti-Filho et al., 2003). ...
... In several countries, rearing and mass release of P. bliteus showed promising results, increasing parasitism levels in the field up to 94% (Huerta, Faundez & Araya, 2010;Ferreira-Filho et al., 2015). However, this parasitoid failed to establish viable populations in regions of warm climate, such as some parts of California (Daane, Sime &Paine, 2012) andin Brazil (Ferreira-Filho et al., 2015). Thus, it is likely that an effective control of G. brimblecombei using P. bliteus would demand periodic mass releases, increasing the financial costs of this strategy. ...
Background
The red gum lerp psyllid, Glycaspis brimblecombei Moore (Hemiptera: Psyllidae), an eucalypt insect pest from Australia, was reported in Brazil in 2003. This study evaluated damage patterns of this pest on Eucalyptus camaldulensis Dehn (Myrtaceae) and its hybrids E. urophylla X E. camaldulensis (urocam) and E. urophylla X E. grandis (urograndis). In addition, parasitism rates of Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) on G. brimblecombei collected on different eucalypt genotypes are reported.
Methods
Plantation plots of three eucalypt genotypes were evaluated over one year. The eucalypt leaves were collected and examined for attack by G. brimblecombei . Nymph parasitism of G. brimblecombei by P. bliteus was recorded.
Results
Damage by G. brimblecombei was lower on the hybrid genotypes and on the adaxial surface of the eucalypt leaves. G. brimblecombei egg and nymph density were negatively correlated with monthly rainfall. Nymph parasitism of G. brimblecombei by P. bliteus was low (2.9%) independent of genotype and did not vary throughout the year.
Discussion
Our data indicate the use of less susceptible eucalypt genotypes (e.g., hybrids) as an alternative to G. brimblecombei management. Because of the current low mortality rates for G. brimblecombei resulting from P. bliteus parasitism, biological control with this natural enemy is not recommended as a management strategy for G. brimblecombei .
... With the exception of P1 and male HH, success rate of species detection by species-specific multiplex PCR of post-emergence mummies was high and comparable to the success rate in a previous study that applied the same method to investigate diversity, host specificity and coevolutionary patterns in parasitoid communities of eight psyllid species . The poor detection of P1 may be due to its apparent lack of a pupal sheath (Sullivan et al., 2006) left behind in the mummy. This was evident given that P1 mummies were translucent and a pupal sheath was not observed. ...
Insect herbivore outbreaks frequently occur and this may be due to factors that restrict top-down control by parasitoids, for example, host–parasitoid asynchrony, hyperparasitisation, resource limitation and climate. Few studies have examined host–parasitoid density relationships during an insect herbivore outbreak in a natural ecosystem with diverse parasitoids. We studied parasitisation patterns of Cardiaspina psyllids during an outbreak in a Eucalyptus woodland. First, we established the trophic roles of the parasitoids through a species-specific multiplex PCR approach on mummies from which parasitoids emerged. Then, we assessed host–parasitoid density relationships across three spatial scales (leaf, tree and site) over one year. We detected four endoparasitoid species of the family Encyrtidae (Hymenoptera); two primary parasitoid and one heteronomous hyperparasitoid Psyllaephagus species (the latter with female development as a primary parasitoid and male development as a hyperparasitoid), and the hyperparasitoid Coccidoctonus psyllae. Parasitoid development was host–synchronised, although synchrony between sites appeared constrained during winter (due to temperature differences). Parasitisation was predominantly driven by one primary parasitoid species and was mostly inversely host-density dependent across the spatial scales. Hyperparasitisation by C. psyllae was psyllid-density dependent at the site scale, however, this only impacted the rarer primary parasitod. High larval parasitoid mortality due to density dependent nymphal psyllid mortality (a consequence of resource limitation) compounded by a summer heat wave was incorporated in the assessment and resulted in density independence of host–parasitoid relationships. As such, high larval parasitoid mortality during insect herbivore outbreaks may contribute to the absence of host density dependent parasitisation during outbreak events.
... With the exception of P1, detection of parasitoid DNA in mummies was high (> 60%). The poor detection success of P1 may be due to its apparent lack of a pupal sheath in the mummy [63], as also seen by the translucent appearance of mummies. Furthermore, in cases of hyperparasitism, DNA of the primary parasitoid host ...
Background: Parasitoids are hyperdiverse and can contain morphologically and functionally cryptic species, making them challenging to study. Parasitoid speciation can arise from specialisation on niches or diverging hosts. However, which process dominates is unclear because cospeciation across multiple parasitoid and host species has rarely been tested. Host specificity and trophic interactions of the parasitoids of psyllids (Hemiptera) remain mostly unknown, but these factors are fundamentally important for understanding of species diversity, and have important applied implications for biological control.
Results: We sampled diverse parasitoid communities from eight Eucalyptus-feeding psyllid species in the genera
Cardiaspina and Spondyliaspis, and characterised their phylogenetic and trophic relationships using a novel approach that forensically linked emerging parasitoids with the presence of their DNA in post-emergence insect mummies. We also tested whether parasitoids have cospeciated with their psyllid hosts. The parasitoid communities included three Psyllaephagus morphospecies (two primary and, unexpectedly, one heteronomous hyperparasitoid that uses different host species for male and female development), and the hyperparasitoid, Coccidoctonus psyllae. However, the number of genetically delimited Psyllaephagus species was three times higher than the number of recognisable morphospecies, while the hyperparasitoid formed a single generalist species. In spite of this, cophylogenetic analysis revealed unprecedented codivergence of this hyperparasitoid with its primary parasitoid host, suggesting that this single hyperparasitoid species is possibly diverging into host-specific species. Overall, parasitoid and hyperparasitoid diversification was characterised by functional conservation of morphospecies, high host specificity and some host switching between sympatric psyllid hosts.
Conclusions: We conclude that host specialisation, host codivergence and host switching are important factors driving the species diversity of endoparasitoid communities of specialist host herbivores. Specialisation in parasitoids can also result in heteronomous life histories that may be more common than appreciated. A host generalist strategy may be rare in endoparasitoids of specialist herbivores despite the high conservation of morphology and trophic roles, and endoparasitoid species richness is likely to be much higher than previously estimated. This also implies that the success of biological control requires detailed investigation to enable accurate identification of parasitoid-host interactions before candidate parasitoid species are selected as biological control agents for target pests.
... Glycaspis brimblecombei infestations are easily recognizable by the presence of conical white shields known as lerps, each inhabited by a single nymph and attached to the foliage covering both surfaces of the leaves. These lerps are built from faecal excretions of the nymphs that harden upon exposure to the air (White, 1972), providing protection against natural enemies (predators and parasitoids) and avoiding desiccation during development (Sullivan et al., 2006;Sharma et al., 2013). The damage caused by this psyllid is mainly a result of nymphs and adults feeding by sucking phloem from the leaves. ...
The red gum lerp psyllid G lycaspis brimblecombei is an invasive insect species, native from A ustralia, that specifically feeds on E ucalyptus trees. It has invaded several countries throughout the world. In A rgentina, it was first recorded in 2005, although little is known about its ecology in the region.
We assessed G . brimblecombei population development on E ucalypus camaldulensis and E ucalyptus dunnii using samples of branches for the immature stages and yellow sticky traps for the adults. We also identified the meteorological variables associated with changes in the red gum lerp psyllid abundance.
The abundance of eggs, nymphs and adults stages of G . brimblecombei was significantly greater on E . camaldulensis than on E . dunnii in the 2 years of the survey.
G lycaspis brimblecombei development was complete on E . camaldulensis where all instars were present, even in the unfavourable seasons. The full development of the psyllid population was not observed in E . dunnii where a high mortality of the first and second nymphal instars was detected.
Temperature and relative humidity were the variables that mostly affected red gum lerp psyllid abundance, whereas no effect of rainfall was detected.
... The exoskeleton of the dead parasitized hosts forms an easily recognized mummy, and the psyllid nymph is completely consumed as the parasitoid nearly finishes development. The white P. bliteus larva can be seen throughout the mummified exoskeleton of G. brimblecombei, which becomes transparent (Sullivan et al., 2006). P. bliteus was accidentally introduced into Brazil and was first reported soon after its host in 2003 (Berti-Filho et al., 2003). ...
... In several countries, rearing and mass release of P. bliteus showed promising results, increasing parasitism levels in the field up to 94% (Huerta, Faundez & Araya, 2010;Ferreira-Filho et al., 2015). However, this parasitoid failed to establish viable populations in regions of warm climate, such as some parts of California (Daane, Sime &Paine, 2012) andin Brazil (Ferreira-Filho et al., 2015). Thus, it is likely that an effective control of G. brimblecombei using P. bliteus would demand periodic mass releases, increasing the financial costs of this strategy. ...
Background. The red gum lerp psyllid Glycaspis brimblecombei Moore (Hemiptera: Psyllidae), an eucalypt insect pest from Australia, was reported in Brazil in 2003. This study evaluated damage patterns of this pest and the parasitism rates of Psyllaephagus bliteus (Hymenoptera: Encyrtidae) on E. camaldulensis and its hybrids E. urophylla X E. camaldulensis and E. urophylla X E. grandis . Methods. Plantation plots of three eucalypt genotypes were evaluated over one year. The eucalypt leaves were collected and examined. Results. Damage by G. brimblecombei was lower on the hybrid genotypes and on the adaxial surface of the eucalypt leaves. Glycaspis brimblecombei egg and nymph density correlated negatively with monthly rainfall. Nymph parasitism by P. bliteus was low (2.9%) independent of genotype and did not vary throughout the year. Discussion. The use of less susceptible eucalypt genotypes (e.g., hybrids) seems to be an alternative to G. brimblecombei management because mortality rates for this pest resulting from P. bliteus parasitism were low.
... In the laboratory, the development of parasitoids from egg to adult takes 23–13 days, in the temperature range 22–30 °C (Daane et al., 2005). Host-feeding by adult P. bliteus can occur in all nymphal stages, and causes the death of the younger nymphs (Sullivan et al., 2006). In Portugal, P. bliteus was observed for the first time in 2011, four years after its host's detection, and is now established wherever G. brimblecombei is present (Dhahri et al., 2014). ...
... However, these predators can only lower the pest population slightly and do not provide adequate and economical suppression (Dahlsten et al. 2003;Tovar & Herrera 2001). This could be due to the fact that predators cannot pierce the hard protective shells (approximately 1.1-mm thick) of G. brimblecombei nymphs (Sullivan et al. 2006;Wilcken et al. 2003). ...
The genus Eucalyptus, native to Australia, is the host of psylloid insects such as the red gum lerp psyllid Glycaspis brimblecombei, a major Eucalyptus pest introduced into Brazil among other countries. The encyrtid Psyllaephagus bliteus is a primary parasitoid used in the biological control of G. brimblecombei. This study aimed to determine the parasitism of G. brimblecombei by P. bliteus released in eucalyptus plantations. Investigations were carried out in a 19-ha eucalyptus plantation comprised of 9-year-old Eucalyptus camaldulensis (Myrtaceae) in the munici-pality of Luiz Antônio, São Paulo State, Brazil. Twenty P. bliteus pairs were released at five points in the study area between May and September 2006 and 2007 ap-proximately every 20 days. For evaluation of parasitism, ten leaves per twig were randomly selected and unpar-asitized nymphs of G. brimblecombei, mummies (parasitized nymphs of G. brimblecombei) and empty mummies (after emergence of P. bliteus adults) were counted on their abaxial and adaxial parts before and after each release of P. bliteus. The parasitism rates of G. brimblecombei in 2006 and 2007 were 0.21–5.92% and 0.28–7.03% in the control; these values rose to 28.28–78.57% and 30.32–79.34%, respectively, in areas involved in parasitoid release. Parasitism levels of G. brimblecombei nymphs in areas with P. bliteus re-lease were affected by the environmental temperature, which is discussed as a potential limitation to the estab-lishment of this parasitoid and to its effectiveness as a biological control agent.
