EFFECT OF APPLICATION RATES OF DISULFOTON AND PHORATE, AND OF IRRIGATION ON APHID CONTROL AND RESIDUES IN CANNING PEAS

Abstract

Measurable residues of disulfoton (O, O-diethyl S-2-(ethylthio) ethyl phosphorodithioate) and phorate (O, O-diethyl S-(ethylthiomethyl) phosphorodithioate) were found in pea vines but not in shelled peas 76 days after furrow treatments at time of seeding. Residues of disulfoton were related to application rates. Insecticide treatments satisfactorily controlled pea aphids, Acyrthosiphon pisum (Harris) from plant emergence to harvest. Disulfoton at 1.12-kg/ha active ingredient was as effective as phorate at 2.24 kg/ha. Irrigation, where moisture was not a limiting factor, did not enhance disulfoton or phorate translocation, but by delaying pea maturity it reduced tenderometer readings and yields of shelled peas. Insecticide treatments did not affect yields or tenderometer readings, or produce phytotoxic effects.