DISAPPEARANCE OF CAPTAN FROM FIELD- AND GREENHOUSE-GROWN TOMATO FRUIT IN RELATIONSHIP TO TIME OF HARVEST AND AMOUNT OF RAINFALL

Abstract

Between 1982 and 1984 studies were conducted into captan disappearance from the fruit of field- and greenhouse-grown tomatoes (Lycopersicon esculentum L.). Captan was applied to field-grown tomatoes at 1.8 kg ha⁻¹ a.i. in August 1982 and 1983, and to greenhouse tomatoes at 1.9 kg ha⁻¹ in May 1983 and 1984. Initial residues in both cases were below 1.5 mg kg⁻¹. Significant declines in residue occurred by day 2 (1983) or day 3 (1982) for field-grown tomatoes and residues were below 0.1 mg kg⁻¹ by day 14 (1982) or day 15 (1983). The decline in field tomatoes was correlated with rainfall. With greenhouse tomatoes the residue did not significantly decline by day 15 in 1983 and significantly increased by day 15 in 1984.Key words: Tomato (field and greenhouse), Lycopersicon esculentum L., captan, residue decline