Efficacy of various types of pyrethroid compounds against Tyrophagus putrescentiae and Dermatophagoides farinae

Abstract

In comparison with fenitrothion and diazinon, various types of pyrethroid compounds were evaluated for their control efficacy against Tyrophagus putrescentiae and Dermatophagoides farinae by the culture mixing method. Some new findings were obtained in the study on the pyrethroid structure-activity relationships. Against T. putrescentiae, esters of cyclopropanecarboxylic acid derivatives with phenoxybenzyl alcohol such as phenothrin, fenpropathrin, K-1917,permethrin, KA-1918,K-1919,K-1920,and K-1810 were found to be effective. The activity of these compounds at a concentration of 500ppm was equivalent to that of the reference compounds, fenitrothion and diazinon. The results also showed that the pyrethroid compounds were generally more effective to D. farinae than T. putrescentiae. In particular, phenothrin, cyphenothrin, fenpropathrin, permethrin, cypermethrin, KU-1686 and fluvalinate exhibited high control efficacy against D. farinae at a concentration of 100ppm, being as active as diazinon. The introduction of a cyano group into the α-position of the benzylalcohol moiety of tested pyrethroid compounds usually caused reduction in control efficacy against these mites; this is a different phenomenon from that observed in the tests of these compounds for the insecticidal activity. Moreover, some pyrethroid compounds which were reported as having high acaricidal activity against tetranychid mites on plants were not always effective against mites in the house, indicating that there were some differences in the mode of action of pyrethroids among mite species, as well as between mites and insects.