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Spodoptera frugiperda (J E Smith) (fall armyworm) (Lepidoptera: Noctuidae), is a key pest of maize that has recently entered in India causing damage and yield loss. A biocontrol-based integrated pest management (IPM) strategy was designed and evaluated in farmer’s field during rabi and kharif season (2018–2019). IPM strategy comprising installation of controlled release FAW pheromone traps, four releases of Trichogramma pretiosum Riley, two sprays of neem oil, one spray of each Bacillus thuringiensis (NBAIR-BT25) and Metarizium anisopliae (NBAIR Ma-35) resulted in 76 and 71.64% egg mass; 80 and 74.44% larval population reduction at 60 days after treatment during rabi and kharif season, respectively. Cob yield per acre in biocontrol-based IPM field was higher than the farmer’s practice (6–7 sprays of emamectin benzoate 5% SG) during both the seasons, and it resulted in 38.3 and 42.29% gain in yield per acre during rabi and kharif, respectively. Therefore, this module forms a base to manage the fall armyworm in an eco-friendly and farmer friendly manner. Future research with other alternatives has also been discussed.

The present study was conducted to collect and identify the species of trichogrammatids from eggs of lepidopteran pests infesting the diverse cropping systems in the country. A total of 28 plant species were inspected for the collection of lepidopteran eggs either through collection of insect eggs or by placing sentinel egg cards. The species such as Trichogramma chilonis Ishii, T. achaeae Nagaraja and Nagarkatti, T. danausicida Nagaraja, Trichogrammatoidea bactrae Nagaraja and Tr. armigera Manjunath were recorded naturally occurring with 12 species of lepidopteran insect pests. In nature, the parasitism rate varied from 5.35 to 82.25% by the associated trichogrammatids. A total of 596 sentinel trap cards were placed in the agricultural, vegetables, fruits crops, and grasses on the bunds of fields to trap the egg parasitoids present in the different habitat. Through sentinel cards, three species, viz. , T. chilonis , T. achaeae and Tr. bactrae were found inhabit the vegetables and ornamental crops. The percentage of adult emergence from the sentinel trap cards ranged from 70.59 to 100.0%. Natural parasitism of Tr. bactrae recorded for the first time on the eggs of Lampides boeticus L. infesting wild species of Crotalaria . In addition, the natural parasitism of Tr. armigera and Tr. bactrae on the eggs of L. boeticus laid on either cultivated or wild relatives of Crotalaria in undisturbed habitat had higher natural parasitism due to their bright yellow flower attracts parasitoids to parasitize the eggs and conserve these egg parasitoids. Recently, natural parasitism of Trichogramma sp. was recorded on invasive fall armyworm, Spodoptera frugiperda (J.E. Smith) infesting maize in Karnataka. Based on the present work, there could be choice of selecting right species which occur naturally on individual crops.

Trichogramma chilonis Ishii is an endoparasitic wasp widely used as a biological control agent of economically important pests. However, absence of genetic information on T. chilonis hampers further research, especially at the molecular level. Here, we performed the first RNA-Seq of the adult T. chilonis. A total of 18,372,639 high-quality reads were generated using Illumina pair-ended sequencing platform. De novo assembly resulted into 24,488 transcripts, with mean length and N50 values of 1444.2 bp and 2667 bp, respectively. Of the transcripts, 14,643 exhibited putative homology with class Insecta proteins from UniPROT database. To understand the contig functions, gene descriptions, gene ontology and cluster of orthologous group annotations were analyzed. Following functional annotation, a number of transcripts encoding detoxification, target receptor action and olfaction- related proteins were identified and analyzed. In addition, 4520 transcripts containing simple sequence repeats, ranging from dinucleotide to hexanucleotide repeats were discovered, with trinucleotide being the most enriched repeats. This new sequence resource will shed light on various molecular mechanisms in T. chilonis and related species.

A field trial was conducted in a farmer’s field by integrating biocontrol agents, a multiple insecticide tolerant strain (MITs), Trichogramma chilonis and 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. chilonis releases of 100,000 parasitized eggs ha− 1 were 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. xylostella larvae 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.

Fall armyworm, Spodoptera frugiperda (J.E. Smith), is a polyphagous pest invaded India and seriously threatened maize and other crops. The detailed information on its occurrence and damage severity in the invaded regions are limited. In this study, we assessed the occurrence, incidence and damage severity of fall armyworm in 126 maize fields in 10 districts of Karnataka during the rainfed condition. Further, potential co-occurrence of this pest with native stem borers and its natural enemies explored to tackle this pest. Survey reports revealed that the fall armyworm was well distributed across the maize growing regions of Karnataka with 44–100% field infestation. The damage incidence of S. frugiperda was 22.13–46.83% with damage severity 0 to 4.9 on the 0 to 9 scale. The larval count was 0.93 ± 0.17 to 3.07 ± 0.58 per 10 plants across the locations. The co-occurrence of S. frugiperda with the native maize stem borers, Chilo partellus (Swinhoe) and Sesamia inferens (Walker) was less than 5% of the plants. It shows that S. frugiperda had dominated the native stem borers causing significant damage to maize. This study found five parasitoids parasitizing the egg, egg-larval, larval and larval-pupal stages of S. frugiperda. Trichogramma chilonis Ishii and Telenomus remus Nixon egg parasitism rates were 15.81–23.87% and 5.44–8.78%, respectively. The larval parasitoids caused 9.18% parasitism of S. frugiperda larvae. Trichogramma chilonis appeared as a major natural enemy. These data provide an important baseline for the development of sustainable management strategies for S. frugiperda.

Trichogrammatids (Hymenoptera: Trichogrammatidae) are the most important egg parasitoids widely used in different biocontrol programs worldwide. Since there are several species, strains, and ecotypes available, correct identification is the first step for successful biological control programs. Morphological identification remains complex due to subtle difference in male genetalia, therefore alternative molecular techniques were employed for rapid and reliable identification of this group of parasitoids. Furthermore, many of the field collected specimens are females, which are not identifiable using morphological keys. This study was carried out to unravel the discrimination success in the two molecular marker loci cytochrome oxidase I (COI) and internal transcribed spacer-2 (ITS-2) region of trichogrammatids. In achieving these objectives, the single specimen of 22 trichogrammatids belonging to 19 species were subjected to DNA extraction, PCR amplification, and sequencing. Additionally, we obtained homologous sequences from GenBank and sequences in BOLD database to understand internal relationships between the trichogrammatids. Bayesian inference phylogenetic analysis conducted with 84 and 76 sequences of COI and ITS-2 loci respectively and studied discrimination among the different species. Based on trees in comparison, we observed that there was a total of 10 and 6 out of 19 species correctly discriminate with COI and ITS-2 respectively. Our result revealed that the ITS-2 gene was less divergent than the COI gene in the majority of species and failed to differentiate all terminal clades. Therefore, we recommend that COI is suitable as the primary DNA barcode locus in trichogrammatids. Overall, we suggest that COI gene has higher discrimination power and can be considered as an appropriate molecular marker for species identification in trichogrammatids.

The host egg preference studies revealed that Trichogramma chilonis, which was collected from 8 crops, preferred the eggs of Corcyra cephalonica most (84.8% parasitism), followed by Chilo partellus (55.1%) and Helicoverpa armigera (47.9% parasitism) and Samia ricini eggs were least preferred, T. achaeae was recorded from eggs collected from 3 crops only. The parasitoids obtained from rice, sugarcane, cabbage and dolichos were more robust rather than other 4 crops. The parasitoids collected from sugarcane showed strong recognition to the crop when released back on sugarcane, while parasitoids from other crops did not show any pattern of host-plant recognition. Sugarcane appeared to be the most preferred crop for T. chilonis releases with parasitism of 30.5%, followed by paddy (18.9%), cotton (18.3%) and tomato was the least preferred host plant.

The South American tomato moth Tuta absoluta (Meyrick) is a devastating pest of tomato. In the present study Tuta-adapted strains of Trichogramma were evaluated. Amongst the three species, Trichogramma achaeae Nagaraja and Nagarkatti, Trichogramma pretiosum Riley and Trichogrammatoidea bactrae Nagaraja could parasitise T. absoluta eggs and the parasitism rates were 5.0%, 51.1% and 68.2% respectively. Adults emerged from the parasitized T. absoluta eggs (4.8%, 97.5% and 90.0% adult emergence respectively). The F1 generation adults of T. pretiosum could parasitise 29% of Corcyra cephalonica Stainton eggs, while the other two species were not successful in parasitizing. In addition, four 'hymenopteran' parasitoids, viz. T. achaeae , Neochrysocharis formosa (Westwood), Habrobracon sp. and Goniozus sp. were also observed to be associated with T. absoluta in the fields during the surveys undertaken in southern India.