2015 Volume 30 Issue 1 Pages 13-18
Insecticide residues of 20% propetamphos MC were quite variable depending on the test materials. Ceramic tile was highest, followed by plywood, aluminum, cork, and chlorinated vinyl, when soaked for five minutes in a diluted solution. The MC particles were stable for two months or more on the surface of the test materials. The initial kill effect of the chemical was very high in each material, showing 100% mortality up to 320 times dilution against a susceptible strain of both sexes of the German cockroach, but 80 times dilution was needed for a good kill against a field-collected colony of the same species. There were no differences up to 320 dilution in each material. However, with 640 dilution or more, cork and aluminum decreased in mortality. The residual efficacy of the MC formulation was very high with 40 times dilution, indicating a 100% kill effect for four months in every material; 80 times dilution in cork was not sufficient whereas other materials maintained a good effect.
