Dissipation study of Quinalphos (25 EC) in/on brinjal and soil.

A field experiment was conducted at Agricultural Research Station, Durgapura, Jaipur during kharif 2008 to study the dissipation of Quinalphos (25 EC) in/on brinjal and soil, when sprayed at its recommended dose (375 g a.i. ha(-1)) and double of the recommended dose (750 g a.i. ha(-1)). The residue data revealed the magnitude of dissipation and persistence by calculating safety parameters like RL(50) and T(tol). The initial deposit of Quinalphos in brinjal at 375 and 750 g a.i. ha(-1) were recorded as 0.0866 and 0.1517 mg kg(-1), respectively which reached to below detectable level (0.01 mg kg(-1)) in 7 and 10 days at recommended (375 g a.i. ha(-1)) and double of the recommended dose (750 g a.i. ha(-1)), respectively. The residues, however, had a half life value (RL(50)) of 2 days for lower dose and 3 days for higher dose. Hence 6 and 9 days waiting period was suggested for recommended and double of the recommended dose, respectively. No residues were detected in soil in treated plots at both the treatment levels 30 days after the spray of insecticide to the crop.