Abstract

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Studies were undertaken to establish dissipation dynamics of commonly used insecticides at recommended dose both in open field and poly house situations to assess the differences in rate of dissipation, and also to recommend Pre-Harvest Intervals based on MRLs established by CAC and FSSAI. Utilizing dimethoate 30% EC @ 300 g a.i. ha^-1, λ-cyhalothrin 5% EC @ 15 g a.i. ha^-1, phosalone 35% EC @ 450 g a.i. ha^-1, flubendiamide 20% WG, profenophos 50%EC @ 500 g a.i. ha^-1 sprays and capsicum samples collected at regular intervals were analyzed for residues.. The dissipation pattern of insecticides varied in poly houses and open fields, where initial deposits were comparatively higher and dissipated slowly in poly houses, Dimethoate initial deposits (0.19 mg kg^-1) are less than FSSAI MRL of 2 mg kg^-1, hence a PHI of 1 day can be recommended. In case of poly house, initial deposit of 2.42 mg kg^-1 was observed and hence a safe waiting period of 7 days can be recommended since FSSAI MRL is 2 mg kg^-1. As no MRLs are available for lambda-cyhalothrin, PHI of 5 can be recommended as residues dissipated to BDL, though the initial residues are 0.16 mg kg^-1 and 0.37 mg kg^-1 in open fields and poly house, respectively, due to very less field dose. In case of phosalone, initial deposits of 5.35 mg kg-1 were recorded in poly house and hence a safe waiting period of 10 days should be recommended since FSSAI MRL is 1 mg kg^-1. Spray of flubendiamide at recommended dose resulted in 1.19 mg kg-1 initial deposit which dissipated to BDL by 15th day in poly house. However, as the Codex MRL is 2 mg kg-1, a PHI of 1 day is ideal for food safety. As per the Insecticide Act, 1969, profenofos is not recommended for use, but when sprayed at farmer’s dose on capsicum, 3.71 mg kg-1 and 2.24 mg kg^-1 initial deposits were recorded in poly house and open field, respectively. Codex suggests MRL as 10 mg kg^-1, hence it can be concluded that profenofos application does not leave residues above MRL. Out of five insecticides tested in poly house phosalone, flubendiamide and profenophos residues are found in capsicumes up to 10 days, while dimethoate and lambda-cyhalothrin are detected up to 7 days. Whereas in open field phosalone and profenophos residues are found up to week while dimethoate, lambda-cyhalothrin and flubendiamide are detected up to five days.

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