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Browsing Thesis by Author "AHMAD, MD. ABBAS"
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ThesisItem Open Access POPULATION DYNAMICS AND MANAGEMENT OF MAJOR INSECT PESTS ON BLACK GRAM(Dr.RPCAU, Pusa, 2021) N, SRIKANTH; AHMAD, MD. ABBASA study was taken up on “Population dynamics and management of major insect pests on black gram” at Research Farm, Tirhut College of Agriculture, Dholi (Muzaffarpur) in summer, 2021. The black gram variety SML 613 was taken as a test variety for the research programme. The observations recorded showed up to six species as major pests in black gram. Whitefly was first seen starting at 11th standard week (1.02 whiteflies/ 5 plants) which increased slowly and attained maximum population (16.4 whiteflies/ 5 plants) during 18th standard week whereas the incidence of thrips on 14th standard week (2.40 thrips/ 5 inflorescences) followed by gram pod borer and bean bug during 15th standard week and green plant bug and pod bug started from 16th standard week and maximum numbers were found at 18th week in whitefly (16.40) and green plant bug (2.15) and 19th week in thrips(15.71), gram pod borer (12.07), pod bug (3.60) and bean bug (2.67) after which the population was observed to be decreasing up on crop maturity. The relative abundance of different pest species of black gram was found to as, whitefly dominant throughout the crop period which was observed starting early stages of crop growth which was followed by thrips and gram pod borer which were found to be dominating during flowering and pod formation stage later on which the dominance of pod sucking bugs viz., green plant bug, pod bug and bean bug were found dominating among the pest complex. All the major insect pests observed were positively correlated to maximum and minimum temperature with whitefly, thrips as well as gram pod borer were significantly positively correlated. Whereas Evening relative humidity was having a significant negative impact on all the major pests except pod bug and bean bug which were non-significant but negative. All treatments proved superior significantly with control to reduce whitefly, thrips and gram pod borer. It was ranging from 32.21 to 77.11 per cent, 32.44 to 81.54 per cent and 19.79 to 76.97 per cent reduction over control in whitefly, thrips and gram pod borer among different treatments among which diafenthiuron 50 WP @ 0.125% was recorded significantly superior over others in managing whitefly (77.11%), thrips (81.54%) and gram pod borer (76.97%). The lowest pod damage was observed in diafenthiuron 50 WP (3.16%) which was succeeded with imidacloprid 17.8 SL (4.28%) and maximum was found to be in seed treated with imidacloprid 70 WS. Highest seed yield (859 kg/ha) was recorded with diafenthiuron 50 WP which is statistically superior among all treatments with maximum returns benefited with a highest cost-benefit ratio of 4.92:1 which was in close range with thiamethoxam 25 WG with 4.78:1. The residues of imidacloprid 17.8 SL and thiamethoxam 25 WG quantified with HPLC showed LOQ of 0.05 mg kg-1. Henceforth, safe consumption of black gram seeds following good agricultural practices (GAP) was suggested with a PHI of 28 days.