Effect of posttreatment temperature on the toxicity of five synthetic pyrethroids toTetranychus urticae Koch (Acari: Tetranychidae)

Abstract

The synthetic pyrethroids bioallethrin, d-phenothrin, and fenvalerate, when tested by the slidedip technique, were more toxic to female two-spotted spider mites, Tetranychus urticae Koch, at 30~ than at 20~ LC~o values differed by 1.7-, 3.8-, and 5.3-fold, respectively. Two other synthetic pyrethroids, flucythrinate and cyfluthrin, gave similar toxicity values at these two temperatures. The greater sensitivity of T. urticae at a warmer temperature to the first three pyrethroids differs from insect toxicity studies, which often show negative temperature relationships.

Temperature relationships in pyrethroid toxicity to the two?spotted spider mite, Tetranychus urticae Koch

“…This finding is in agreement with those reported by Everson and Tonks, 1981;Subramanyam and Cutkomp, 1987;Eesa and Moursy, 1990. Toxicity of fenvalerate showed no significant change within any of the temperature ranges tested on mite nymphs.…”

“…little has been published on temperature relationships in pyrethroid toxicity to mites, in contrast to many reports on insects. A positive correlation of measured pyrethroid toxicity to mite species with temperature after treatment has been documented in quite a few studies (Everson and Tonks, 1981;Subramanyam and Cutkomp, 1987;Eesa and Moursy, 1990). In a previous publication, we reported, for the first time, a negative temperature coefficient in cypermethrin toxicity to the fruit tree false spider mite, Cenopalpus pulcher (Eesa and Moursy, 1990).…”

Effects of temperature on acaricidal and insecticidal activities of the benzoylureas flucycloxuron and diflubenzuron

“…An example is found with the pyrethroids bioallethrin, d-phenothrin and fenvalerate. These compounds show positive temperature coefficients on adults of Tetranychus urticae, the two-spotted spider mite, but generally negative temperature coefficients on insects (Subramanyam & Cutkomp, 1987a).…”