Persistence of Low-Volume and Standard Formulations of Malathion on Lima Bean Foliage

Publisher Website
Google Scholar
Abstract
Chemical analyses and bioassays showed that applications of low-volume (LV) undiluted technical malathion applied in the laboratory to lima bean foliage with apparatus that insured uniform distribution produced a higher initial residue than formulations of malathion in an oil solution or in water emulsion, probably because degradation took place at different rates. An initial residue of LV malathion of 6.25 µg/cm2 declined to 1.2 µg/ cm2 in 8 days and dropped below detectable limits in 12 days. Initial residues of 5.2 or 4.5 µg/cm2 of malathion from the water and oil formulations declined to 2.9 and 2.1 µg/cm2, respectively, in 2 days and dropped below detectable limits in 4 days. When adult Mexican bean beetles, Epilachna varivestis Mulsant, were fed leaves treated with the 3 formulations, the bioassays correlated well with chemical analyses. No mortality occurred on 9-day-old residues from the water or oil formulations, but 70% mortality occurred on 22-day-old residues from LV applications. Washing removed residues completely from leaves treated with the water emulsion, removed an intermediate amount from leaves treated with the oil formulation, and removed the least when LV applications were made.

This publication has 4 references indexed in Scilit: