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The jute hairy caterpillar, Spilosoma obliqua (Lepidoptera: Erebidae) is considered as one of the major threats to jute cultivation. The best eco-friendly methods to combat these jute pests involve administration of nano-biopesticides, as a successful alternative to the toxic chemicals. In this study, a nano-biopesticide formulation containing green synthesized silver nanoparticles (Ag NPs) using Ocimum sanctum leaf extract has been proposed. The characterization studies confirmed significant interactions between the Ag NPs and bioactive components in the nano-biopesticide formulation. The comparative analysis of the aforementioned larval mortality showed better responses in the nano-biopesticide formulation rather than the crude (pure) leaf extract. The LC 50 values were calculated both for the nano-biopesticide formulation and pure extract after 24, 48 and 72 h of treatment. The nano-biopesticide formulation was found to exhibit the lowest and much promising LC 50 value of 93.21 ppm, 23.38 ppm, 5.96 ppm relative to that of LC 50 values of 1590.74 ppm, 459.30 ppm, 102.68 ppm respectively for the crude leaf extract. The synergistic interactions between the components in the nano-biopesticide formulation can be associated with its greater effectiveness as a promising toxicant to the larvae of the jute caterpillar compared to the mere leaf extract, thereby, demonstrating a greener and safer method for effective pest management.

The effect of three green gram cultivars (PDM 54, PUSA BAISAKHI and SAMRAT) on the biology of Spilosoma obliqua Walker (Lepidoptera: Arctiidae) was studied using age-stage, two-sex life table. We also studied food utilization efficiency measures of larvae on green gram cultivars. The nutritional and antinutritional factors of leaves of green gram cultivars were determined. The preadult development time of S. obliqua was shortest on PDM 54 (35.54 days) and longest on SAMRAT (39.29 days). The fecundity was highest on PDM 54 (318.32) and lowest on SAMRAT (250.20). The net reproductive rate ( R 0 ) ranged from 37.53 on SAMRAT to 79.58 on PDM 54. The intrinsic rate of increase ( r ) was higher on PDM 54 (0.1148 day −1 ) and PUSA BAISAKHI (0.1018 day −1 ) than SAMRAT (0.0875 day −1 ). The finite rate of increase (λ) was lowest on SAMRAT (1.0915 day −1 ). Mean generation time ( T ) was shortest on PDM 54 (38.12 days) and longest on SAMRAT (41.42 days). Population projection revealed that the population growth was slowest on SAMRAT. The growth rate of sixth instar larvae was highest on PDM 54 and lowest on SAMRAT. The lower level of nutritional factors such as total carbohydrates, proteins, lipids, amino acids and nitrogen content, and a higher level of antinutritional factors such as total phenols, flavonols and tannins influenced higher development time and lower fecundity of S. obliqua on SAMRAT than other cultivars. These findings suggested that SAMRAT is a less suitable cultivar to S. obliqua than other cultivars, and this cultivar can be promoted for cultivation.

Entomopathogenic nematodes (EPNs) from the families Steinernematidae and Heterorhabditidae are biocontrol agents for the management of a wide range of insect pests. There is a tremendous opportunity for the discovery of new nematode strains and species adapted to local environmental conditions and insect pests. Therefore, in the present study, efforts were made to isolate EPN strains/species from the Northwestern Himalayas (NWH) region. The soil samples were collected from different locations in Almora, Uttarakhand. The collected soil samples were baited with Corcyra cephalonica , and they were observed regularly for their mortality. EPNs were isolated from the cadaver using the white trap method. Based on morphological and morphometrical studies, Heterorhabditis sp. VLEPN01 shows a resemblance to the species of Heterorhabditis indica . Further identity was confirmed with molecular characterization using the rDNA ITS marker. The sequence of this native EPN isolate revealed 99.87% similarity with H. indica isolated from Mizoram, Northeastern India (MF618314). The efficacy of EPN was evaluated against major insect pests of the NWH region. The results showed that H. indica VLEPN01 is capable of causing 100% mortality in fall armyworm ( Spodoptera frugiperda ), white grub ( Anomala dimidiata ), tobacco caterpillar ( Spodoptera litura ), and pod borer ( Helicoverpa armigera ) under laboratory conditions. Hence, H. indica VLEPN01 can be utilized for field testing in the management of insect pests occurring in the NWH region.

Background Spilosoma (=  Spilarctia ) obliqua (Walker) (Lepidoptera: Arctiidae), once considered as a sporadic pest, is now considered as a major and polyphagous pest widely distributed throughout India. Recent outbreaks of this pest were manifested in both jute and sunnhemp. During a survey in and around adjoining villages of I.C.A.R-C.R.I.J.A.F, Barrackpore, an epizootic was observed in the field population of S. obliqua caused by a nucleopolyhedrosis virus. Hence, an attempt was made to isolate, characterize using electron microscopy and assess the efficacy of S. obliqua nucleopolyhedrosis virus under laboratory and field conditions. Results Electron microscopic studies revealed typical baculovirus occlusion bodies of type nucleopolyhedrosis virus with tetrahedral and triangular in shape with the size ranging from 2.55 to 2.90 µm, with an average size of about 2.72 µm. Bioassay studies showed the larval mortality at low concentration of Spob NPV, i.e., 2.42 × 10 4  POBs/ml. The virus-infected S. obliqua was identified through the amplification of polyhedrin, polh gene sequences with the available sequences in public database, GenBank, NCBI. The sequence data generated for the polyhedrin gene were deposited in GenBank, and accession number was obtained, MN648213. Field experiment revealed 50.52, 63.25 and 82.91% larval reductions, respectively, at 2, 4 and 7 days after spray of S. obliqua nucleopolyhedrosis virus. Conclusion The present study revealed that foliar application of S. obliqua nucleopolyhedrosis virus was very effective in causing mortality against S. obliqua larvae and thus can be used as an effective microbial bioagent in the integrated pest management of the caterpillar, S. obliqua.

Jute hairy caterpillar, Spilosoma (= Spilarctia ) obliqua (Walker) (Arctiidae: Lepidoptera), is an irregular and polyphagous insect pest that occurs all over India. A severe natural viral epizootic was observed in the field population of S. obliqua in jute. The virus was characterized as Spilosoma obliqua nucleopolyhedrovirus (SpobNPV NBAIR1) based on morphological, biological, and molecular characterization. Under scanning and transmission electron microscopy (SEM and TEM), the occlusion bodies (OBs) of SpobNPV NBAIR1 appeared as both tetrahedral and triangular with the size ranged from 1.04-1.72 μm. The results on the bioassay studies revealed that the lowest LC 50 value of 2.93 OBs/mm 2 by leaf disc bioassay against the second instar S. obliqua showed its high virulence. The identity of SpobNPV was further confirmed by the amplification of polyhedrin gene (NCBI GenBank accession no. MK288145). Eleven species of lepidopteran insects, viz., Spodoptera litura , S. exigua , S. frugiperda , Helicoverpa armigera , Plutella xylostella , Amsacta albistriga , Maruca vitrata , Trichoplusia ni , Pieris brassicae , Agrotis ipsilon , and Bombyx mori , were not susceptible to the infection with SpobNPV NBAIR1. Field experiments on jute crop revealed 68.92, 78.59, and 93.16% reduction in larval population of S. obliqua at 3, 4, and 7 days post spray of SpobNPV NBAIR1 (1.5 × 10 12 OBs/ha at 2 ml/l), respectively. The present study is a renewed effort in the management of S. obliqua by the new strain of SpobNPV NBAIR1.

Background The gram pod borer ( Helicoverpa armigera Hubner), Bihar hairy caterpillar ( Spilosoma obliqua Walker), tobacco caterpillar ( Spodoptera litura Fabricius) and root knot nematode ( Meloidogyne incognita (Kofoid and White) Chitwood) are the major insect pest and nematodes infesting mungbean, urdbean and other legumes. Bacillus thuringiensis ( Bt ) is a promising biocontrol agent that helps in managing the above pest. Deploying Bt biopesticides instead of chemical pesticides in legume cultivation enhances the soil health substantially. The present study envisages morphological, molecular cum biochemical characterization, entomotoxicity and nematotoxicity potential of four indigenous Bt strains (Ak 2 .IIPR, F8.IIPR, F5.IIPR and F6.IIPR) along with HD1 (standard check from BGSC). Results The SEM micrograph analysis of above four Bt strains along with F1.IIPR revealed the presence of different combinations of insecticidal crystal proteins, viz. cuboidal crystal (CC), bipyramidal crystal (BC), spherical crystal (SC) and irregularly pointed crystal (IC). This was further confirmed by PCR amplification of Cry1 , Cry2Aa , Cry2Ac , VIP3A and chi36 gene-specific primers and their phylogenetic analysis. F8.IIPR and Ak 2 .IIPR recorded the highest toxicity index against second-instar S. obliqua larvae (292.56 and 174.55), H. armigera (150.00 and 113.65) and S. litura (210.71 and 114.19) based on probit analysis. F5.IIPR (91.67%) and F8.IIPR (89.00%) recorded the highest juvenile mortality against M. incognita , followed by Ak 2 .IIPR (70.33%). The protein profiling of supernatant of terrific broth inoculated with F8.IIPR indicated the presence of VIP3A and Cry1I. Conclusion The present study concluded that F8.IIPR and Ak 2 .IIPR were potential Bt strains isolated from Indo-Gangetic plains which is having both entomocidal and nematicidal properties. Further, these strains were deposited at national repository, ICAR-NBAIM with the following accession no.: NAIMCC-SB-065 and NAIMCC-SB-066, respectively. These strains can be formulated as microbial biopesticide.

Background Sesame ( Sesamum indicum L.) is a widely used oil seed crop throughout the world but its productivity is extremely low due to use of low yielding cultivars as well as biotic stress for the major pest Spilosoma obliqua Walker. But even today, farmers generally use broad-spectrum synthetic pesticides for their management injudiciously without considering any economic threshold (ET) limit and creates ecosystem crisis. So, time-based ecologically sustainable management of the said pest and selection of a superior cultivar of sesame was studied by stage-specific two-sex pooled life table and nutritional ecology of S. obliqua on three sesame cultivars (Rama, Shubhra and Amrit) along with their economic thresholds (ETs) in 2019. Results The nutritional ecology and population dynamics of S. obliqua were significantly affected by the host phytoconstituents in terms of host suitability or susceptibility (Rama > Shubhra > Amrit). The mean EIL and ETL for S obliqua was 36.316 ± 3.911 and 33.243 ± 2.734 pests/m 2 , respectively on cv. Rama that were significantly ( F 2,6  = 5.421–5.435; P  ≤ 0.042) lower than Shubhra and Amrit. For a single pest per m 2 (30 ± 2 plants/m 2 ) the possible time that can be taken to reach EIL (Ti) and ETL (Tt) were 39.132 ± 3.969 and 38.132 ± 3.969 days, respectively on cv. Rama which were also significantly ( F 2,6  = 26.551; P  = 0.001) lower than the other cultivars. The seed yield and benefit cost ratio (BCR) were 857.099 ± 0.000 (Kg/ha) and 0.607 ± 0.000, respectively for cv. Rama that were significantly ( P  < 0.05) lower than the others. Conclusions It will enable growers to find the most preferred cultivar (Rama > Shubhra > Amrit) based on BCR values irrespective of their biotic resistance (Rama < Shubhra < Amrit) due to host antibiosis. Even, the ETs-based time series for judicious management of the pest along with carbon sequestration efficiency (CSE) will also support superiority of the cultivars (Rama > Shubhra > Amrit) towards climate smart pest management (CSPM) of sesame and or other such crops in near future.

An experiment was conducted to introduce the entomopathogen Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) as an endophyte in jute ( Corchorus olitorius ), a bast fibre crop through seed treatment. Colonization of root, leaf, stem, capsule, and seed were assessed through plating on selective medium and PCR based detection using B. bassiana specific SCAR markers. Endophytic colonization was detected in all the plants grown from treated seeds, but all the plant parts were not colonized. Colonization was detected in leaves, stems, and green capsules but not in roots and seeds. The endophytic colonization was influenced by both plant part and sampling period. Colonization was greater in leaves (55.87%) compared to stems (12.53%) and capsules (42.44%). The percent colonization was higher in case of 60 days old plants (43.34%) than in 30 days (23.89%) and 120 days (35.39%) old plants. As B. bassiana has already been reported to be pathogenic on jute pests, namely semilooper ( Anomis sabulifera ) and bihar hairy caterpillar ( Spilosoma obliqua ), its season long endophytic colonization within jute plant suggests a novel approach of biological control of these pests through seed treatment with the entomopathogen.

The oviposition, feeding behavior, and development of the jute hairy caterpillar Spilosoma obliqua Walker (Lepidoptera: Arctiidae) was studied on one cultivated jute species, Corchorus olitorius L. (‘JRO-204') (Malvales: Malvaceae), and 5 wild jute species, viz., C. tridens L., C. trilocularis L., C. pseudo-olitorius Islam & Zaid, C. aestuans L., and C. fascicularis Lamarck under laboratory conditions with a temperature of 27 ± 2 °C and relative humidity of 80 ± 5%. These host plant species had considerable influence on oviposition, larval feeding behavior, larval survival, larval weight, pupation, pupal weight, and adult emergence. Significant differences were observed in oviposition preference based on numbers of eggs laid by the adults. The mean number of egg clusters differed significantly with 3.6 ± 0.3, 3.0 ± 0.6, 3.3 ± 0.3, 3.0 ± 0.6, 1.0 ± 0.6, and 2.0 ± 1.2 on C. olitorius, C. fascicularis, C. trilocularis, C. pseudo-olitorius, C. tridens, and C. aestuans, respectively. The C. pseudo-olitorius and C. aestuans were less preferred with the lowest mean numbers of eggs per cluster (77.2 ± 8.2 and 75.2 ± 38.8, respectively) compared with 174.0 ± 2.7 on C. olitorius. With respect to feeding preferences, most larvae (53.9 ± 3.4%) preferred C. olitorius as compared with 1.6 ± 0.02% and 7.2 ± 1.5% of larvae feeding on C. aestuans and C. tridens, respectively. Only 2 species, namely C. trilocularis and C. olitorius, supported complete larval development. The growth of 3rd instars indicated a maximum antibiosis effect by C. tridens and C. aestuans on S. obliqua. Total protein content in the host plants had a significant positive correlation with the larval survival, weight, pupation, and adult emergence of S. obliqua, whereas polyphenol oxidase and total phenol were negatively correlated. The effect of wild jute species with higher phenol and peroxidase as host plants manifested adversely on larval development, growth, survival, pupation, and adult emergence, which indicates the antibiosis mechanism of resistance.

Hexane and acetone extracts of Trichilia connaroides leaves were evaluated for their biological activity against the Bihar hairy caterpillar Spilosoma obliqua Walker, a destructive pest of crop, medicinal and ornamental plants. Fresh caster (Ricinus communis) leaves treated with a range of concentrations (1–10%) of the extracts were offered to 2nd instars for 120 h, followed by untreated leaves until pupation. Acetone extracts exerted better growth-regulatory properties than hexane extracts, shown by morphogenic malformation and adverse effects on the insect's larval duration, pupal duration, adult emergence and fecundity.