• Current Research on Agriculture and Life Sciences
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• v.11
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• pp.101-110
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• 1993

The residues of combined insecticide of polynactin complex(tetranactin) and BPMC were determined to establish an index for the safety use to apple. Evaluation was made on residual concentration of tetranactin and BPMC in apple as a function of application frequency and date when the combined insecticide of tetranactin and BPMC was sprayed into apple. Their persistence in soil were also studied under the field and laboratory conditions. Recovery percentage from apple was ranged from 74.0 to 77.5 in tetranactin, 87.1 to 83.6 in BPMC, those from soil was 82.3 to 88.4 in tetranactin, 83.6 to 887.1 in BPMC. The minimum detectable limits of tetranactin and BPMC were 0.01ppm in apple pulp and 0.03ppm in apple peel and soil. The residue percentage of tetranactin and BPMC in the peel and pulp part of apple was about 96 in peel part by five sprays up to 3th day before harvest. The residues of tetranactin and BPMC in apple are proved to 0.39ppm and 0.75ppm by five sprays up to 30days before harvest. Maximum residue limit(MRL) of BPMC for fruits was established of 0.3ppm in Environment Protection Agency of Korea, and thus it is suggested that the preharvest intervals of combined insecticide for apple could be 30 days with twice spray. The half life of tetranactin in soil under field and laboratory conditions was 6.9 and 24.4 days, and in case of BPMC was 6.3 and 23.2 days, respectively.