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Pink bollworm, Pectinophora gossypiella (Saunders) infestation on Bt cotton is a major concern to cotton production in India. The genetic diversity and phylogeographic structure of the insect in light of PBW resistance needs to be revisited. The objective of this study was to identify different haplotypes of pink bollworm and their distribution in India. To achieve this we studied the population structure in 44 cotton growing districts of India. The partial mitochondrial COI sequence analyses of 214 pink bollworm populations collected from 44 geographical locations representing 9 cotton growing states of India were analysed. Genetic diversity analysis exhibited presence of 27 haplotypes, among them Pg_H1 and Pg_H2 were the most common and were present in 143 and 32 populations, respectively. Distributions of pairwise differences obtained with partial COI gene data from the overall Indian populations are unimodal, suggesting population expansion in India. Significant neutrality test on the basis of Tajima’ D and Fu’s Fs presented a star-shaped haplotype network together with multiple haplotypes. The unimodal mismatch distribution, rejection of neutrality test with significant negative values supported the theory of demographic expansion in cotton pink bollworm populations in India. Genetic data not only provides us with a perspective of population genetics, but also that the two populations of pink bollworm, those occurring early in the season are genetically close to the late season populations with respect to their partial CO1 region. Resistance to Cry toxins does not seem to have had an impact on this region of the mt DNA in populations of pink bollworm.

India is the world’s largest cotton producer and the only country that grows all four cultivated cotton species. There have been very few studies on the diversity and abundance of natural enemies of cotton insect pests in these cultivated cotton species. Therefore, the current study (2016–2018) was conducted to assess the diversity and abundance of natural enemies that cultivated cotton species harbour. Phule Dhanwantari, Suraj, Suvin, RCH-2, and DCH-32 were the five genotypes used in the study, each with a distinct genetic background. Using the adiv 2.0.1 and vegan R packages, we identified significant differences in natural enemies in terms of species diversity, richness, evenness, and abundance. Analysis of Similarity (ANOSIM) and Non-metric Multidimensional Scaling (NMDS) indicated substantial differences in the natural enemy community structure among the examined genotypes. A total of 17,279 natural enemies were collected and identified across genotypes from seven predatory families and five parasitoid families. The percentage share of these natural enemy families across genotypes and years, in descending order, is Coccinellidae (28.23%) < Tachinidae (19.23%) < Braconidae (12.68%) < Chrysopidae (11.65%) < Chalcididae (9.41%) < Aphelinidae (6.33%) < Pentatomidae (3.29%) < Ichneumonidae (2.37%) < Syrphidae (2.33%) < Vespidae (1.81%) < Asilidae (1.79%) < Geocoridae (0.89%). Coccinellidae, Tachinidae, Braconidae, Chrysopidae, Chalcididae, and Aphelinidae are the six major families that account for more than 85% of all recorded natural enemies. These six families have a higher percentage share in Phule Dhanwantary (90%) compared to the other genotypes. The conservation and better utilization of these natural enemies are crucial for the ecological and safe management of insect pests in the cotton ecosystem.

Background Insecticidal proteins from the Bacillus thuringiensis ( Bt ) marks the genetically modified cotton crop that was commercialized in India in March 2002 for the control of lepidopteron bollworms. Despite organized initial control, the pink bollworm (PBW), Pectinophora gossypiella (Saunders), adapted itself to cry toxins resulted in field control failures in 2016 and 2017.  The present study was designed to understand the survival and development of PBW populations differing in susceptibility to Cry toxins on Bt and non-Bt plants.  Results For assessment of infestation, populations were collected from different cotton growing states. Per cent infestation of flowers and green bolls in the study areas were in the range of 3.09–29.26 and 36–91.20% for flowers and green bolls, respectively. Among different locations highest magnitude of resistance to Cry1Ac (371.8-fold) and Cry2Ab (4214.3-fold) was spotted in late season populations of Rajkot collected from bolls. Further, in order to confirm field level resistance of surviving larvae on high and low concentrations of Cry toxins, larvae were pooled and subjected to boll bioassays. Results revealed that, none of the larvae from susceptible populations survived on BGII bolls. Although, the same populations showed a survival of 38 and 32%, which led to 80% locule damage on non- Bt cotton. Maximum survival (32%) and locule damage (70%) was observed for Maharashtra (F-H) Cry2Ab and Gujarat (B-H) Cry2Ab populations recorded 36% survival and 70% mortality, respectively, on BGII cotton and 58.33% survival and 60% locule damage on non- Bt cotton, respectively. Populations derived from survivals on low concentrations produced the lowest survival and locule damage on Bt cotton. Maximum number of mines on epicarp (2.4 mines/boll) was recorded by susceptible population on NBt cotton. Green bolls of Bt and NBt cotton did not differ in the number of mines. Conclusion It was concluded that none of the larvae from susceptible populations survived on BGII bolls. Although, the same populations showed a survival of 38 and 32%, which led to 80% locule damage on non- Bt cotton

Whitefly Bemisia tabaci (Gennadius) is an important pest of cotton in India. The study of taxonomic diversity and its distribution on cotton is lacking. Such studies are necessary to identify the genetic groups of B. tabaci and its distribution on cotton in India. The proper identification of genetic groups and their distribution, which, ultimately, can lead to the timely development and utilization of management practices. The current study was undertaken to explore the genetic diversity and phylogeographic structure of B. tabaci from all the three major cotton growing zones representing different agro-climatic conditions of India. 290 partial mitochondrial Cytochrome Oxidase I (mt COI) sequences of whitefly population of six major cotton-growing states covering 22 districts were used in the analysis. Phylogenetic analysis revealed the presence of two monophyletic clades, Asia I and Asia II1 genetic groups represents South-Central India and North India respectively. Asia II1 is found more predominately distributed in the cotton leaf curl virus (CLCuV) disease-prone north Indian cotton-growing states. Higher genetic divergence (16.8–19.2%) was observed between the populations of Asia I and Asia II1 genetic group. Genetic differentiation analysis confirmed the phylogeographic structure of B. tabaci as isolated by distance. Our results in mapping the distribution of genetic groups in cotton ecosystems paved the way for the further studies and formulation of area-wide management practices for cotton whitely in India.

The insecticidal and phytotoxicity activities of oils from castor (Ricinus communis), pongamia (Pongamia glabra), sesame (Sesamum indicum), neem (Azadirachta indica) and neem based formulations in combination with a detergent Powder as a surfactants (0.1%) were studied against adults of Bemisia tabaci at their peak activity period during 2016–17 and 2017–18 seasons under laboratory and field conditions. Among the oils, castor oil caused a reduction of whitefly populations by 55.4 & 64.2 and 40.5 & 42.8% under laboratory and field conditions, respectively during both the years, pongamia oil 58.4 & 51.7 and 44.9 & 39.2%, sesame oil 45.5 & 56.4 and 30.8 & 36.9%. Neem oil and its formulated products were reported to be comparatively less effective in reduction of whitefly population after chemical treatments i.e. difenthiauron 50 WP (76.2 & 81.5 and 63.5 & 55.2% under laboratory and field conditions, respectively). Phytotoxicity observed after application of recommended doses of castor, pongamia, sesame and neem oil and its formulated products did not cause any problem on tender cotton leaves. The detergent based solutions were difficult to mix and oily layers appeared after mixing, hence mixing the oils and detergent solutions with sticker Triton-X-100 @1.0 ml/l is more effective and easy to apply on cotton plants.

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a serious pest of cotton that inflicts huge economic losses. Excessive use of chemical pesticides for its management causes environmental pollution and pesticide resistance. Six bioassay methods and ten entomopathogenic fungal strains (EPFs) were evaluated to find out the suitable bioassay method and the most virulent strain(s) for management of B . tabaci under laboratory and polyhouse conditions. The highest tenderness and survival period (> 30 days) of the leaves and increasing trend in nymphal mortality was recorded in a new modified polyhouse bioassay method (NMPBM). NMPBM was found to be effective, simpler, and less labor intensive for evaluating large numbers of EPF strains. Twelve newly isolated EPF strains were characterized based on their morphological and molecular characteristics. The highest whitefly nymphal mortality (at 10 7 conidia ml −1 ) was recorded by Beauveria bassiana (Bb)-4511 (95.1%), Bb-4565 (89.9%), and Metarhizium anisopliae -1299 (86.7%) at the seventh day post inoculation. However, the overall bioefficacy index was higher in Bb-4511 (78.1%), Cordyceps javanica (Cj)-102 (77.0%), and Cj-089 (75.4%) than other EPF strains. The lowest values of LC 50 and LC 90 were with Cj-089 and Bb-4511. The field deployment of effective formulation of these most virulent EPF strains might be helpful for managing B . tabaci populations and CLCuD incidence under insecticide resistance management programs.

Beauveria bassiana (Bal.-Criv.) is an important entomopathogenic fungus being used for the management of various agricultural pests worldwide. However, all strains of B. bassiana may not be effective against whitefly, Bemisia tabaci , or other pests, and strains show diversity in their growth, sporulation, virulence features, and overall bioefficacy. Thus, to select the most effective strain, a comprehensive way needs to be devised. We studied the diversity among the 102 strains of B. bassiana isolated from 19 insect species based on their physiological features, virulence, and molecular phylogeny, to identify promising ones for the management of B. tabaci . Strains showed diversity in mycelial growth, conidial production, and their virulence against B. tabaci nymphs. The highest nymphal mortality (2nd and 3rd instar) was recorded with MTCC-4511 (95.1%), MTCC-6289 (93.8%), and MTCC-4565 (89.9%) at a concentration of 1 × 10 6 conidia ml −1 under polyhouse conditions. The highest bioefficacy index (BI) was in MTCC-4511 (78.3%), MTCC-4565 (68.2%), and MTCC-4543 (62.1%). MTCC-4511, MTCC-4565, and MTCC-4543 clustered with positive loading of eigenvalues for the first two principal components and the cluster analysis also corresponded well with PCA (principal component analysis) (nymphal mortality and BI). The molecular phylogeny could not draw any distinct relationship between physiological features, the virulence of B. bassiana strains with the host and location. The BI, PCA, and square Euclidean distance cluster were found the most useful tools for selecting potential entomopathogenic strains. The selected strains could be utilized for the management of the B. tabaci nymphal population in the field through the development of effective formulations. Key points • 102 B. bassiana strains showed diversity in growth and virulence against B. tabaci. • Bioefficacy index, PCA, and SED group are efficient tools for selecting potential strains. • MTCC-4511, 4565, and 4543 chosen as the most virulent strains to kill whitefly nymphs.

The role of cytochrome P450 monooxygenase in pyrethroid resistance was studied in different strains of the cotton bollworm, Helicoverpa armigera, from India. Filed collected strains of Nagpur and Delhi were compared to the laboratory reared population. The results showed a high resistance to deltamethrin, α-cypermethrin, and β-cyfluthrin. The results also showed that this resistance could be reduced by using piperonyl butoxide (PBO). The Nagpur and Delhi strains were found to have a 2.40 and 1.79 fold higher monooxygenase activity compared to a susceptible strain. A strong, positive correlation between monooxygenase activity and pyrethroid resistance was observed (r = 0.86 - 0.98). The relative expression of the housekeeping gene, EF-1α, and three P450 genes, was studied in the 5th instar larval midgut of the three strains. Out of the three P450 genes examined, expression of CYP6B7 mRNA was not detected in the midgut of the susceptible strain though it was highly expressed in the resistant strains. The midgut of the Nagpur strain had a 2.60 fold overexpression of CYP6B7 mRNA compared to the moderately resistant, Delhi strain. The mRNA of CYP4G8 and CYP6B2 were not overexpressed in either the Nagpur or Delhi strain. The results indicated that the elevated cytochrome P450 monooxygenase activity is associated with pyrethroid resistance in Indian strains of H. armigera, and CYP6B7 could be the P450 form responsible for pyrethroid resistance.

The performance of cyanobacteria and Trichoderma based biocontrol formulations was evaluated in two cotton varieties (Gossypium hirsutum F1861 and Gossypium arboreum CISA 310). Evaluation of mortality after 4 weeks revealed a significant reduction, particularly in G. hirsutum F1861, with values of 13 % (lower by 2 % over the Trichoderma commercial biocontrol agent). The percent mortality after drenching with the compost tea prepared using respective formulations, ranged from 28 to 75 % in G. arboreum CISA 310, with significantly lower values of 6–37.3 % in G. hirsutum. The Anabaena laxa RPAN8 formulation showed the lowest mortality. The activity of hydrolytic enzymes—β-1, 3 glucanase (EGase EC 3.2.1.39), β-1, 4 glucanase (EGase EC, 3.2.1.4) and chitosanase (EC 3.2.1.99) showed a significant enhancement in the inoculated treatments (T1–T6), with Calothrix sp. being among the top ranked treatments in both varieties. Comparison of DNA fingerprints (HIP-TG profiles) of rhizospheric soil DNA with those of corresponding pure cultures revealed a high degree of similarity, confirming the colonization of inoculated organisms. An amplicon of 1000 bp was observed in the soil metagenomic PCR-DNA profiles from both varieties, which confirmed the presence of an endoglucanase gene. Comparative analyses of responses of the two varieties revealed that Gossypium hirsutum F1861 showed higher values of hydrolytic enzymes and available N in soil. On the other hand, microbial inoculation elicited higher levels of chitosanase and defense enzyme activity in Gossypium arboreum CISA 310. This represents a first report illustrating the significance of varietal responses in cotton in relation to the efficacy of microbial biocontrol formulations and their establishment in the rhizosphere.

The potential of cyanobacteria-based compost formulations was evaluated in cotton crop at two agro-ecological locations (Nagpur and Sirsa) as plant growth promoting (PGP) and biocontrol agents. Compost-based formulations fortified with Calothrix sp. or Anabaena sp. enhanced germination and fresh weight of plants, and microbiological activity by 10–15%, besides increased available nitrogen (by 20–50%) in soil at Nagpur. In the fungi-infected fields at Sirsa, Anabaena–T. viride biofilmed formulation performed the best, recording 11.1% lower plant mortality than commercial Trichoderma formulation. Scanning electron microscopy confirmed the colonisation of inoculated cyanobacteria/biofilms on roots. Significant correlation between mortality, increased activity of hydrolytic enzymes and fresh weight of plant roots were recorded. Calothrix sp. and Anabaena sp. proved promising as both PGP and biocontrol agents, while biofilmed formulations substantially reduced mortality of cotton plants in sick plots. This study illustrates the promise of cyanobacteria as viable inoculation option for integrated nutrient and pest management strategies of cotton.