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Background: The fall armyworm (FAW), Spodoptera frugiperda(J.E. Smith) (Lepidoptera: Noctuidae) is a highly polyphagous and destructive pest of maize and other cereal crops. Biological control is a potential alternative to chemical insecticides used for the management of FAW in maize. Egg parasitoids are promising biocontrol agents as they kill the insect pest at their egg stage before it hatches, thus preventing the damaging larval stage. Trichogrammais widely used in augmentative biological control of FAW in native and invaded regions. However, FAW lay egg masses in layer by layer and eggs are covered with egg scales, this may affect the performance of Trichogrammaparasitoids. Therefore, the parasitism potential of three Trichogrammaspecies was studied on eggs with or without scales and layered eggs of FAW, further the impact of parasitoids ovipositor length on parasitism was also determined. This helps to understand the parasitism potential of parasitoids on different egg type for better implementation of biological control programs against FAW. Results: The effect of FAW egg mass with or without scales and layered eggs on the performance of Trichogramma chilonis, T. pretiosumand T. mwanzaiwas studied and results indicated that egg mass scales and the layered eggs were significantly affected the parasitism potential of Trichogrammaspecies, but did not affect the parasitoid emergence. In general, T. chilonisparasitized a higher percentage of eggs with or without scales and layered eggs of FAW than the other two species. T. chilonisand T. mwanzaihad a greater ovipositor length than T. pretiosum. Conclusion: The performance of evaluated Trichogrammaspecies on FAW eggs with or without scales and layered eggs affected the parasitism success. The parasitism success of T. chiloniswas comparably higher than other tested species. Hence, the scales on egg masses and layered eggs of FAW should be taken into account while selecting the Trichogrammaspecies in the biological control of FAW.

A field trial was conducted in a farmer’s field by integrating biocontrol agents, a multiple insecticide tolerant strain (MITs), Trichogramma chilonisand formulation of Bacillus thuringiensis(NBAIR BtG4) with reduced insecticidal spray as a biocontrol-based IPM compared to insecticidal application as a farmer’s practice, for the management of the diamondback moth (DBM), Plutella xylostella(Linnaeus) (Lepidoptera: Plutellidae) infesting cabbage. Six T. chilonisreleases of 100,000 parasitized eggs ha− 1were applied. Along with parasitoid release, a liquid formulation of B. thuringiensis(2%) was applied after third and fifth releases of T. chilonis. The number of P. xylostellalarvae were significantly reduced in the field treated with biocontrol-based IPM as compared to farmer’s practice after 30 and 45 days after treatment. After the 45 days, the holes on cabbage leaves were 2.2/plant in the field treated with biocontrol, opposed to 8.0 holes per plant were recorded in the farmer’s practice filed. Only 7% of cabbage head damage was recorded in the field treated with biocontrol, whereas, in farmer’s practice field, those were 32.2%. The cost-benefit analysis showed that integrating these biological control agents along with a reduced number of insecticidal sprays could reduce DBM population and percent head damage with an eventual increase in the yield.

The ability of entomopathogenic nematodes to suppress larval populations of the white grub, Leucopholis lepidophoraBlanchard (Coleoptera: Scarabaeidae), infesting the areca nut palm (Areca catechu) was investigated under field conditions over a 2-year period (2015–2017). Heterorhabditis indicaat two application rates (1.7 × 105and 3.5 × 105IJs palm−1) caused higher percentage reduction of L. lepidophoralarvae than Steinernema abbasiand chlorpyrifos. Chlorpyrifos-treated plots caused higher percentage of reduction of the grub larvae than S. abbasiat the lowest rate (1.7 × 105IJs palm−1). However, S. abbasiat 3.5 × 105IJs palm−1performed at least equally well than the chlorpyrifos treatment. The kernel yield from H. indica-treated plots at 3.5 × 105IJ palm− 1was 85.4% higher than those from water control and 33.3% higher than that in the chlorpyrifos treatment. The kernel yields varied significantly among different treatments. The cost-benefit analysis showed that H. indicais a promising biocontrol agent for the management L. lepidophoracontrol in areca nut field.

Indigenous entomopathogenic nematode, Heterorhabditis pakistanensis, NBAIR H-05 strain was evaluated against diapausing larvae of the Codling moth, Cydia pomonellaL. (Lepidoptera: Tortricidae) at 3 different dosages, i.e., at 15, 20, and 25 gm/ l of water in apple orchards at the district Kargil of Ladakh Region, India, during 2017 and 2018.Two year’s pooled average density of diapausing ranged 34.6 to 56.8 larvae/trunk band before treatment, which declined ranging 43.85 to 86.27 % with respect to different treatments of entomopathogenic nematode at concentrations between 7.5 × 105IJs to 1.25 × 106IJs/tree. Percent reduction in larvae over control varied from 41.78 to 85.77% for 7.5 × 105IJs and 1.25 × 106IJs respectively. Two-year pooled data indicated larval mortality between 39.85 and 73.38% and 4.0 to 12.89% with respect to different treatments at 48 and 72 h respectively, with statistically significant difference (P= ˂ 0.001). Increase in dosage of nematode formulation from 15 gm to 25 gm resulted in increased larval mortality (r= 0.92**). Post wetting of trunk band after 24 h in each treatment resulted in significantly higher larval mortality than non-post wetting. There was non-significant difference (t= 0.83) between larval mortality with respect to treatments during 2017 and 2018.