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Fusarium wilt, caused by (Fusarium udum Butler), is a significant threat to pigeonpea crops worldwide, leading to substantial yield losses. Traditional approaches like fungicides and resistant cultivars are not practical due to the persistent and evolving nature of the pathogen. Therefore, native biocontrol agents are considered to be more sustainable solution, as they adapt well to local soil and climatic conditions. In this study, five isolates of F. udum infecting pigeonpea were isolated from various cultivars and characterized morphologically and molecularly. The isolate from the ICP 8858 cultivar displayed the highest virulence of 90%. Besides, 100 endophytic bacteria, 100 rhizosphere bacteria and three Trichoderma spp. were isolated and tested against F. udum isolated from ICP 8858 under in vitro conditions. Out of the 200 bacteria tested, nine showed highest inhibition, including Rb-4 (Bacillus sp.), Rb-11 (B. subtilis), Rb-14 (B. megaterium), Rb-18 (B. subtilis), Rb-19 (B. velezensis), Eb-8 (Bacillus sp.), Eb-11 (B. subtilis), Eb-13 (P. aeruginosa), and Eb-21 (P. aeruginosa). Similarly, Trichoderma spp. were identified as T. harzianum, T. asperellum and Trichoderma sp. Notably, Rb-18 (B. subtilis) and Eb-21 (P. aeruginosa) exhibited promising characteristics such as the production of hydrogen cyanide (HCN), cellulase, siderophores, ammonia and nutrient solubilization. Furthermore, treating pigeonpea seedlings with these beneficial microorganisms led to increased levels of key enzymes (POD, PPO, and PAL) associated with resistance to Fusarium wilt, compared to untreated controls. In field trials conducted for four seasons, the application of these potential biocontrol agents as seed treatments on the susceptible ICP2376 cultivar led to the lowest disease incidence. Specifically, treatments T2 (33.33) (P. aeruginosa) and T3 (35.41) (T. harzianium) exhibited the lowest disease incidence, followed by T6 (36.5) (Carbendizim), T1 (36.66) (B. subtilis), T4 (52.91) (T. asperellum) and T5 (53.33) (Trichoderma sp.). Results of this study revealed that, P. aeruginosa (Eb-21), B. subtilis (Rb-18) and T. harzianum can be used for plant growth promotion and management of Fusarium wilt of pigeonpea. [ABSTRACT FROM AUTHOR]

Nicotine is a highly addictive alkaloid and a neurostimulator found in tobacco that causes addiction in humans and makes tobacco a high-demand commercial product. It is popularly used for recreational purposes and is a harmful substance (Oral LD50 value for rat is 50 mg/kg) and causes addiction. The metabolites of nicotine such as the Tobacco-specific Nitrosamines (TSNAs) are hazardous substances whose metabolites are highly electrophilic and form DNA adducts, which will initiate the process of carcinogenesis. TSNAs are formed during curing, storage and fermentation due to the nitrosation of nicotine and other tobacco alkaloids. TSNAs are used as biomarkers for cancer risk assessment in humans exposed to tobacco and its products. To determine the occasional formation of TSNAs in tobacco-feeding insects, 5th instar larvae of Spodoptera litura and their faeces were analyzed for the presence of N′-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) along with the stored tobacco leaves (PT-76) using an Agilent 6470B LC–MS/MS system following ISO/DIS 19290:2015 protocol. The larvae are extracted in a buffered acetonitrile–water extraction and the amount of TSNAs are quantified in multiple reaction monitoring (MRM) mode. 20 μ l of each extracted and cleaned up sample was injected into the LC–MS/MS system for quantification. The Limit of Detection (LOD) and Limit of Quantification (LOQ) were 0.001 mg/kg and 0.005 mg/kg for all the tested nitrosamines. NNN was found to be 0.361 mg/kg, 0.340 mg/kg, and 5.66 mg/kg in insect whole-body samples, faeces, and tobacco leaves, respectively. NNK was found to be 0.060 mg/kg, 0.035 mg/kg and 0.93 mg/kg in insect whole body samples, faeces and tobacco leaves, respectively. However, NNAL was not detected in both the insect's whole body and faeces. Recoveries ranged between 95 and 98% for all compounds when spiked at LOD and LOQ. The presence of TSNAs is a biomarker for cancer risk and their presence in insects would point to cancer risk assessment in tobacco feeding insects and any possible TSNA-detoxifying pathways in insects that might prevent mutagenesis caused these compounds. [ABSTRACT FROM AUTHOR]

Whitefly, Bemisia tabaci (Gennadius) is a cryptic species complex that infests various plant species and act as a vector for many plant viruses all over the world. To understand the B. tabaci cryptic species diversity in Bihar more comprehensively, interhost and interlocation surveys were conducted during the year 2020-2021. The genetic variability among 29 populations (16 interhost and 13 interlocation) was explored using nuclear markers viz. Random Amplified Polymorphic DNA (RAPD), Simple Sequence Repeats (SSR) along with mitochondrial marker, mtCOI. The dissimilarity coefficients of 29 populations clustered in a dendrogram with RAPD and SSR primers showed that interlocation populations were less diverged than the interhost populations. Bayesian phylogenetic analysis of 657 bp mtCOI sequences identified the presence of four cryptic species viz. Asia I, Asia II 1, Asia II 7 and China 3 belonging to two genetic groups (Asia and China) with high variations in interhost unlike in interlocation. Among the four cryptic species, Asia I was the most prevalent in Bihar, establishing 86.20% of all the sequenced samples and Asia II 7 and China 3 were reported for the first time in Bihar region. We believe that the information generated in this study is important from the perspective of identifying cryptic species diversity and to develop long term pest management strategies. [ABSTRACT FROM AUTHOR]

Lipaphis erysimi (Lipaphis erysimi erysimi and Lipaphis erysimi pseudobrassicae) group, often known as the mustard or turnip aphid, is one of the most devastating specialist aphid of Rapeseed-mustard, causing yield losses of 9 to 96%. This study was carried out with a goal of precisely identifying the dominant specialist aphid of Rapeseed-mustard and to address the issues such as genetic differentiation from different Rapeseed-mustard growing regions covering all the six zones of India. The dendrogram, Principal component analysis (PCA) and phylogenetic relationships revealed that populations of Jorhat (North Eastern India) were highly diverged. Phylogenetic relationship produced by Tamura 3-parameter with Gamma distribution (T92 + G) model using mtCOI demonstrated the presence of L. e. pseudobrassicae in all of the surveyed locations in India including Chintapalli (Andhra Pradesh) a Southern India, where it was reported for the first time. Neutrality tests viz. Tajima and Fisher test supported neutral theory of evolution. Furthermore, our findings in mapping the distribution of L. e. pseudobrassicae in various locations will pave the way for future research and the development of area-wide management tactics for L. e. pseudobrassicae in India. [ABSTRACT FROM AUTHOR]

The gram pod borer, Helicoverpa armigera (Hübner) is the insect pest of global agricultural importance due to its wide host range and cosmopolitan distribution, which is supported by a strong genetic base. This paper presents genetic diversity of the pest population feeding on different hosts (inter-host) and geographic locations (inter-location) in Uttarakhand Himalayas, India and their micro-evolutionary consequences. A total of 21 inter-host and 17 inter-location populations were studied using both nuclear (SSR markers i.e., 1st tier) and mitochondrial genes (cytochrome b i.e., 2nd tier). In case of inter-host populations, grouping was observed in relation to crop season (Kharif and Rabi), sequential growing of the crops and association of crops with weeds and concurrence of crop growth stages. Interestingly, in both the nuclear and mitogenome analysis, the wheat population stood separate as a major cluster, which might be due to its adaptation towards the crop in recent past in the region. Although there is a differential grouping in SSR and cytb based clustering in inter-location populations, high altitude populations stand separate. The study illustrates ecological and evolutionary driven behavioural adaptations in H. armigera populations in Uttarakhand Himalayan population, India. [ABSTRACT FROM AUTHOR]

The current study aims to identify the resistance mechanisms of fourteen chickpea genotypes against checks and unknown metabolites of selected genotypes against Helicoverpa armigera. In the biophysical context, the highest glandular and non-glandular trichome lengths were present on the leaf surface (GL25016) and pod surface (ICCV92944 and ICCV09103), whereas the highest glandular and non-glandular trichome densities were present on the leaf surface for ICCV97105 and pod surface of ICCV07108 and ICCV14872. The per cent pod damage and Pest Resistance Susceptible Rating (PRSR) for different chickpea genotypes in the field condition varied from 19.94 to 35.67% and 3 to 4 respectively. In the biochemical context, the highest total phenol and tannin content were observed in GL25016, while total flavonoids present in ICCV97105. The lowest protein and highest trypsin content were observed in JG11 and NBeG1004 respectively. The relationship between biological attributes of H. armigera and biochemical constituents in different chickpea genotypes revealed that per cent pod damage had a significant negative correlation with flavonoids. GC–MS analysis of selected chickpea genotype showed the presence of γ-Sitosterol (repellent activity) and 9-Octadecenoic acid (Z) (oviposition deterring and repellent activity), which has been reported in the resistant genotype ICCL86111. Tetradecanoic acid, which has larvicidal and repellent activity were present in ICCV92944. These identified sources of resistance in NBeG1004, ICCV92944, ICCL86111, GL25016 and ICCV97105 genotypes, will aid in their efficacy against H. armigera and resistance breeding. [ABSTRACT FROM AUTHOR]