Determination of reentry interval for cucumber harvesters in greenhouse after application of insecticide methidathion

Abstract

Determination of reentry interval for harvesters after application of insecticide methidathion on cucumber in greenhouse was performed. Dislodgeable foliar residue of methidathion ranged from 12.1∼222.5 ng/cm2 for 7 days after application. First-order rate constant for methidathion residue on foliage was −0.4915, and half-life was 1.4 days. The reentry interval (REI) without personal protective clothing or equipment was calculated as 44 h (1.8 days), which is not practical, because cucumber is usually harvested everyday during production period due to its fast growing characteristics. However, when harvester wear personal protective clothing or equipment, −69 h (−2.9 days) of REI was determined, indicating they could reenter greenhouse on the day of application. Therefore, harvesters must wear personal protective clothing or equipment for safe harvesting activity in cucumber greenhouse on the day of application.