Browsing by Author "Biswajit Das"

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Bioefficacy, environmental safety and synergistic impacts of biorational formulations against whitefly, leafhopper and blister beetle in organic okra ecosystem
(Cambridge University Press, 2021) Satyapriya Singh; Gulab Singh Yadav; Anup Das; Biswajit Das; Hidangmayum Lembisana Devi; Mahadevan Raghuraman; Amit Kumar
Whitefly (Bemisia tabaci Gennadius), leafhopper (Amrasca biguttula biguttula Ishida) and large yellow-banded blister beetle (Mylabris phalerata) cause considerable damage to okra, especially under organic farming. Thus, the present study was carried out to test the bioefficacy and environmental safety of six naturally derived components [indigenous water plant extracts, i.e. chilli (Capsicum annum), garlic (Allium sativum L.) and neem (Azadirachta indica A. Juss.) along with cow urine in three different combinations, one commercial botanical (azadirachtin 0.15%), and two formulated entomopathogenic fungi (Verticillium lecanii and Beauveria bassiana)] on aforesaid pests for two consecutive years at field scale. In addition to this, the eco-toxicological effect of naturally derived components was also studied on natural enemies' populations, viz. spiders and coccinellids. Quaternary mixture application of chilli, garlic, neem leaf and cow urine (CGNC) at 10% w/v was found effective in reducing leafhoppers (94.6%), whiteflies (95.2%) and blister beetle (94.6%) over control. Okra treated with CGNC produced a higher marketable fruit yield (18.44 mg/ha) than those of other treatments. It was also observed that the application of CGNC had no phytotoxic symptoms on okra plants. Application of CGNC was found safer to the natural enemy's population (spiders and coccinellids). Thus, the study suggests that CGNC can be considered as a potential source for managing the population of whitefly, leafhopper and blister beetle without affecting the ecology of natural enemies and it could be a viable eco-friendly option in organic okra production for ensuring food safety and healthy environment. Copyright © The Author(s), 2021. Published by Cambridge University Press.
New lifetime measurement for the 21+ level in Sn 112 by the Doppler-shift attenuation method
(American Physical Society, 2021) A. Kundu; Md.S.R. Laskar; R. Palit; R. Raut; S. Santra; N. Shimizu; T. Togashi; E. Ideguchi; H. Pai; S. Ali; F.S. Babra; R. Banik; Soumik Bhattacharya; S. Biswas; Biswajit Das; P. Dey; R. Donthi; A. Goswami; S. Jadhav; G. Mukherjee; B.S. Naidu; S. Rajbanshi; L.P. Singh; H.P. Sharma; S.S. Tiwary; A.T. Vazhappilly
Levels in the Sn112 nucleus have been excited by inelastic scattering with Cl35 projectile at Elab=195MeV. The Doppler affected ?-ray peak arising from the decay of the 21+ level has been analyzed, using updated methodologies, to extract the level lifetime and corresponding electric quadrupole (E2) transition probability, B(E2;0g.s.+?21+). The present result is discrepant with respect to the results reported from existing lifetime measurements, but in compliance with independent systematic measurements of the low-lying E2 transition strengths in the stable even-mass Sn isotopes, by pure Coulomb excitation as well as heavy-ion induced inelastic collisions. The transition probability also confirms an enhancement in collectivity for the 21+ level, and is found to be in good agreement with generalized seniority model (GSM) as well as state-of-the-art Monte Carlo shell model (MCSM) calculations. Within the realm of the MCSM scheme, the enhancement is understood in terms of oblate deformations for both the 0g.s.+ and 21+ states in Sn112 arising due to strong proton-core excitations and enhanced proton-neutron interactions. In addition, limits for the lifetime of the 31- level and the E1 transition probability, B(E1;31-?21+), have been obtained. ©2021 American Physical Society.
Occurrence, Distribution, Damage Potential, and Farmers’ Perception on Fall Armyworm, Spodoptera frugiperda (J.E. Smith): Evidence from the Eastern Himalayan Region
(MDPI, 2023) Satyapriya Singh; Mahadevan Raghuraman; Manikyanahalli Chandrashekara Keerthi; Anup Das; Saswat Kumar Kar; Biswajit Das; Hidangmayum Lembisana Devi; Sunil Kumar Sunani; Manas Ranjan Sahoo; Ryan Casini; Hosam O. Elansary; Gobinda Chandra Acharya
The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), is a polyphagous non-native pest identified as a serious threat to crop production and food security globally, including in India. Its unintentional introduction and quick coverage in large areas is a serious concern to millions of farmers in the eastern Himalayan region. However, detailed understanding of farmers’ perceptions and the biological attributes associated with the meteorological factors for FAW is limited. The present investigation, which aimed to create baseline data on this pest, concurs with the idea that the FAW is widely dispersed throughout the maize ecosystems of Tripura, with an average infestation rate of 21.33 percent. The severity ranged from 0 to 1.40, with an average leaf damage score of 1 on a 0–4 categorical scale. The findings indicate that pheromone trap catch was significantly correlated with the evaporation rate as other meteorological factors influenced variably. The biological attributes imply that the life cycle was completed in 32.82 ± 0.08 days, with a high fecundity potential (1068.57 ± 4.35 numbers) in controlled conditions (25 ± 1 °C, 70 ± 5% RH). Indigenous natural enemies, such as entomopathogens, spiders, and wasps, were found to be the first defence against this invasive pest. A minority of the population (17.51%) was aware of the incidence of FAW. Furthermore, respondents’ socio-demographic variables were associated significantly with FAW status. This is the first scientific report from the eastern Himalayan region about farmers’ knowledge and awareness of the invasiveness of FAW. This finding enumerates a detailed understanding of FAW from diverse perspectives. Further, the concerted data provide an important baseline that could help the development of holistic management strategies for FAW. © 2023 by the authors.