Systemic Activity of Dimethoate Applied to Cotton Seeds1

Abstract

Dimethoate was not exceptionally effective as a systemic cottonseed treatment against the boll weevil (Anthonomus grandis Boheman) and cotton aphid (Aphis gossypii Glover). Applied as a seed treatment, dimethoate caused considerable reduction in seedling emergence. Studies with P³²labeled dimethoate applied as a cottonseed treatment indicated that the toxicant was most rapidly absorbed 1 to 3 days after planting. Dimethoate seed treatment did not reduce the total emergence of artificially deteriorated seed, but did reduce the rate of emergence somewhat. Seeds deteriorated for 2 days absorbed more dimethoate than seeds deteriorated for 0,1,3, or 4 days. Dimethoate was found to be less toxic than phorate to boll Weevil larvae and adults.