The effect of snowdrop lectin (GNA) delivered via artificial diet and transgenic plants on Eulophus pennicornis (Hymenoptera: Eulophidae), a parasitoid of the tomato moth Lacanobia oleracea (Lepidoptera: Noctuidae)

1999 ◽  
Vol 45 (11) ◽  
pp. 983-991 ◽  
Author(s):  
H.A. Bell ◽  
E.C. Fitches ◽  
R.E. Down ◽  
G.C. Marris ◽  
J.P. Edwards ◽  
...  
2020 ◽  
Vol 113 (6) ◽  
pp. 2959-2971
Author(s):  
Muhammad Hassaan Khan ◽  
Georg Jander ◽  
Zahid Mukhtar ◽  
Muhammad Arshad ◽  
Muhammad Sarwar ◽  
...  

Abstract Agricultural pest infestation is as old as domestication of food crops and contributes a major share to the cost of crop production. In a transgenic pest control approach, plant production of Vip3A, an insecticidal protein from Bacillus thuringiensis, is effective against lepidopteran pests. A synthetic Vip3A gene was evaluated for efficacy against Spodoptera litura Fabricius (Lepidoptera: Noctuidae; cotton leafworm), Spodoptera exigua Hübner (Lepidoptera: Noctuidae; beet armyworm), Spodoptera frugiperda Smith (Lepidoptera: Noctuidae; fall armyworm), Helicoverpa armigera Hübner (Lepidoptera: Noctuidae; cotton bollworm), Helicoverpa zea Boddie (Lepidoptera: Noctuidae; corn earworm), Heliothis virescens Fabricius (Lepidoptera: Noctuidae; tobacco budworm), and Manduca sexta L. (Lepidoptera: Sphingidae; tobacco hornworm) in tobacco. In artificial diet assays, the concentration required to achieve 50% mortality was highest for H. zea followed by H. virescens > S. exigua > H. armigera > M. sexta > S. frugiperda > S. litura. By contrast, in bioassays with detached leaves from Vip3A transgenic tobacco, the time until 50% lethality was M. sexta > H. virescens > S. litura > H. zea > H. armigera > S. exigua. There was no significant correlation between the artificial diet and transgenic plant bioassay results. Notably, the two insect species that are best-adapted for growth on tobacco, M. sexta and H. virescens, showed the greatest time to 50% mortality on Vip3A-transgenic tobacco. Together, our results suggest that artificial diet assays may be a poor predictor of Vip3A efficacy in transgenic plants, lepidopteran species vary in their sensitivity to Vip3A in diet-dependent manner, and host plant adaptation of the targeted herbivores should be considered when designing transgenic plants for pest control.


2021 ◽  
Vol 51 ◽  
Author(s):  
Samanta Souza Restelatto ◽  
Paulo Eduardo Wille ◽  
Nayara Buss ◽  
Cleiton Luis Wille ◽  
Mari Inês Carissimi Boff ◽  
...  

ABSTRACT The looper caterpillar Chrysodeixis includens (Walker) is considered the main defoliating pest in soybean crops, which contributes to yield losses. Delaying its resistance to insecticides is a major challenge in its management. This study aimed to characterize the susceptibility of C. includens to flubendiamide, cyantraniliprole, spinetoram and methomyl, as well as to establish a diagnostic concentration for monitoring resistance. The insecticide was applied to the surface of the artificial diet. For the dose-response curve, concentrations that resulted in 5 to 99 % mortality were used to estimate the lethal concentrations (LC50 and LC99) and resistance ratios (RR50 and RR99). The diagnostic concentrations were based on concentrations that provided 90 to 99 % mortality in the susceptible reference population. For flubendiamide and methomyl, the decrease in the susceptibility resulted in estimated RR50 of 6.2 to 24.2 and 4.4 to 19.6 times, respectively. For cyantraniliprole and spinetoram, there was little difference in susceptibility among the populations, with RR99 lower than 6.1 times. Differences in the susceptibility of C. includens were evident from concentrations of 0.5053, 5.053, 0.1579 and 28.42 μg cm-2, respectively for flubendiamide, cyantraniliprole, spinetoram and methomyl.


1995 ◽  
Vol 85 (4) ◽  
pp. 507-513 ◽  
Author(s):  
G.C. Marris ◽  
J.P. Edwards

AbstractThere is a need to identify potential biological control agents for use against noctuid pests in greenhouses. The gregarious ectoparasitoid Eulophus pennicornis (Nees) attacks a limited range of macrolepidopterous larvae, including those of some important horticultural pest species. Laboratory trials designed to investigate the biology of E. pennicornis on larvae of the tomato moth, Lacanobia oleracea Linnaeus, reveal that wasps preferentially parasitize penulitmate (fifth) or final (sixth) instar hosts. More than two-thirds of wasps lay viable eggs, and individual females oviposit on up to four hosts during their lifespan. Wasp fecundity is high, preadult development is rapid, and offspring show a markedly female-biased sex ratio. Parasitized fifth instar L.oleracea hosts do not grow as quickly as unparasitized larvae, and neither do they undergo normal ecdysis to the final larval stadium. Furthermore, the consumption of artificial diet by parasitized fifth instar hosts is greatly reduced in comparison to that of unparasitized larvae (overall feeding-reduction over a 12 day period was 64.7%). Our results suggest that E. pennicornis affects both the developmental and feeding physiology of host larvae, and that inoculative releases of this parasitoid could provide effective biological control for L. oleracea and other greenhouse pests.


2021 ◽  
Vol 21 (2) ◽  
pp. 158-165
Author(s):  
Adha Sari ◽  
Damayanti Buchori ◽  
Ihsan Nurkomar

Effect of host-larval diet on the host acceptance and host suitability of the egg parasitoid Telenomus remus Nixon (Hymenoptera: Scelionidae) on Spodoptera frugiperda J. E. Smith (Lepidoptera: Noctuidae). The life history of parasitoids is an important factor that can determine their ability to attack a host. The type of food consumed by the host can affect the ability of parasitoids such as host searching behavior, host suitability and host acceptance. In this research, we evaluate the effect of the S. frugiperda larvae diet on its suitability of the eggs produced by the adults for the egg parasitoid Telenomus remus. The research was studied on two types of egg masses of S. frugiperda that obtained from the moths that fed with natural or artificial diet during their larval stages. Parasitoid was reared from both types of hosts. An egg mass consisting of 50 S. frugiperda eggs from both types of hosts was exposed to one egg parasitoid female for 24 hours. S. frugiperda eggs then were reared until the parasitoid adult emerged. Each experiment was repeated 20 times. Host acceptance was observed through the host parasitism rate and its parasitization. Meanwhile, the host suitability was observed through the sex ratio of the emerging parasitoids. The results showed that S. frugiperda eggs reared using artificial diet had a higher parasitism rate (99.33%) than those of natural diet (82.53%). In contrast, the level of parasitization of S. frugiperda eggs reared using natural diet was higher (78.30%) than those of artificial diet (48.34%) because the number of emerging T. remus from S. frugiperda eggs reared using natural diet was also higher than those of artificial diet. However, the sex ratio (F:M) of emerging T. remus from S. frugiperda eggs reared using both of diet was female biased.


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