Time, Temperature and Dosage Relationships of Several Insecticidal Fumigants

Abstract

A laboratory study was made of the relationships of temperature, Exposure time and dosage with the insecticidal action of several space and commodity fumigants. The adult confused flour beetle, Tribolium confusum Jacquelin duVal, was the test insect. The fumigants tested were carbon disulfide, sulfuryl fluoride, acrylonitrile, methyl bromide, ethylene dibromide, carbon tetrachloride, methyl chloroform, ethylene dichloride and chloropicrin. The L.D-50, LD-95 and confidence limits were determined for each of the above fumigants at 2-,5-and 16-hour exposure period sand at temperatures of 40°,60° and 80°F. (4.44°, 15.56°and 26.67°C.). Development of prediction formulas are discussed. With few exceptions, it was found that dosage requirements increase with a decrease in temperature or exposure time. The LD-95 values give essentially straight lines when plotted as Graphs on log-log paper using the products of dosage-time, dosage temperature or time-temperature as the y coordinate and time, temperature or dosage as the x-coordinate. The slope of the equations of the various products of the fumigants is of a similar magnitude regardless of chemical structure or of insect species.