Toxicity and kinetics of spinosad in different developmental stages of the endoparasitoid Hyposoter didymator (Hymenoptera: Ichneumonidae) and its host Spodoptera littoralis larvae (Lepidoptera: Noctuidae)

BioControl ◽  
2007 ◽  
Vol 53 (4) ◽  
pp. 569-578 ◽  
Author(s):  
Pilar Medina ◽  
José Morales ◽  
Guy Smagghe ◽  
Elisa Viñuela
1977 ◽  
Vol 67 (1) ◽  
pp. 142-152 ◽  
Author(s):  
G.W. Miller

AbstractEggs, larvae and pupae of Spodoptera littoralis (Boisd.) were exposed to five non-freezing constant temperatures (13°, 10°, 7°, 4° and 1°C). The period of exposure required to kill eggs and larvae, and to affect pupae seriously, was determined at each temperature. Distinction was made between dead pupae and pupae which were not killed but developed into deformed adults incapable of mating or laying fertile eggs. Probit line analysis was applied to the mortality results and response lines were plotted for all developmental stages at each constant temperature. Observed 100% mortality and computed LD 99 estimates showed that at all temperatures, except 1°C, resistance to cold was minimal at the egg stage, increased in maturing larvae and was at a maximum in the pupal stage, so that the order of the LD 99 values was: pupae (dead)>larvae>eggs. At 1°C the order was: pupae (dead)>30-day-old larvae>eggs>15-day-old and 1-day-old larvae. The LD 99 (days) value decreased with decreasing temperature for all larval stages and for pupae; and for eggs it was greater at 1°C than at 4° and 7°C.


Author(s):  
Moataz A. M. Moustafa ◽  
Eman A. Fouad ◽  
Yasmin Abdel-Mobdy ◽  
Kamirán Áron Hamow ◽  
Zsanett Mikó ◽  
...  

Author(s):  
Peirong Li ◽  
Xinru Li ◽  
Wei Wang ◽  
Xiaoling Tan ◽  
Xiaoqi Wang ◽  
...  

Abstract The oriental armyworm, Mythimna separata (Walker) is a serious pest of agriculture that does particular damage to Gramineae crops in Asia, Europe, and Oceania. Metamorphosis is a key developmental stage in insects, although the genes underlying the metamorphic transition in M. separata remain largely unknown. Here, we sequenced the transcriptomes of five stages; mature larvae (ML), wandering (W), and pupation (1, 5, and 10 days after pupation, designated P1, P5, and P10) to identify transition-associated genes. Four libraries were generated, with 22,884, 23,534, 26,643, and 33,238 differentially expressed genes (DEGs) for the ML-vs-W, W-vs-P1, P1-vs-P5, and P5-vs-P10, respectively. Gene ontology enrichment analysis of DEGs showed that genes regulating the biosynthesis of the membrane and integral components of the membrane, which includes the cuticular protein (CP), 20-hydroxyecdysone (20E), and juvenile hormone (JH) biosynthesis, were enriched. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that DEGs were enriched in the metabolic pathways. Of these DEGs, thirty CP, seventeen 20E, and seven JH genes were differentially expressed across the developmental stages. For transcriptome validation, ten CP, 20E, and JH-related genes were selected and verified by real-time PCR quantitative. Collectively, our results provided a basis for further studies of the molecular mechanism of metamorphosis in M. separata.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Hend O. Mohamed

Abstract Background The Egyptian cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) is one of the major insect pests, causing a significant damage on different cultivated agricultural crops. Developing an alternative non-chemical tool, an effective and environmentally friendly method to suppress pest's infestation is essentially needed. Therefore, biological control by releasing the egg parasitoids could be the most promising tool for integrated pest management. Results This study was designed to evaluate the efficacy of the egg parasitoid, Trichogrammatoidea bactrae Nagaraja (Hymenoptera: Trichogrammatidae) as a bio-control agent against S. littoralis egg masses with different physical characteristics (number of egg layer and degree of scale density) in a no-choice and choice tests, under laboratory conditions. Also, the parasitoids’ fitness in terms of parasitism percentage, developmental period, adults’ emergence percentage, female offspring percentage, and longevity were investigated. The results revealed that T. bactrae wasps had a great ability to parasitize S. littoralis egg masses, but with different rates, related to their layers and scales’ thickness in both tests. The highest parasitism percentage was observed on one-layer eggs, followed by two layers. However, 3-layer eggs were the least preferable one. High numbers of adult emergencies (> 80%) were observed in all tested egg masses, except in the case of 3 layers with high scales. Furthermore, female-biased sex ratios were noticed at all examined eggs, with only the exception of high-scaly eggs with a single layer that recorded the lowest rate (≤ 45%). Besides, the survival of adult female parasitoids was not significantly affected in both tests. Conclusions T. bactrae could be used as a bio-control agent against S. littoralis egg masses with different physical characteristics based on the achieved results.


1992 ◽  
Vol 22 (2) ◽  
pp. 143-148 ◽  
Author(s):  
Ferran Rodriguez ◽  
David L. Hallahan ◽  
John A. Pickett ◽  
Francisco Camps

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