Abstract

The use of acaricides of high toxicity in the production and handling of ornamental plants should be a matter of consumer concern. The susceptibility of two populations of Tetranychus urticae was assessed: one collected from Primula obconica Hance and the other from Convolvulus arvenis L as susceptible reference strain to the acaricides dicofol, abamectin alone and mixed with the surfactant phosphatidylcholine, azadirachtin, sulfur, pyridaben and fenazaquin. The evaluated parameters were mortality, lethal concentration 50% (LC50) and 90% (LC90), lethal time 50% (LT50) and 90% (LT90), effectiveness and index of resistance (IR). The experimental design was completely at random. Each treatment had