Decrease in susceptibility to acetamiprid of Trialeurodes vaporariorum (Westwood) collected in Oita Prefecture

The greenhouse whitefly, Trialeurodes vaporariorum (Westwood) is one of the most devastating insects in Japan and has become a major pest of strawberry and tomato crops in the mountainous regions of Oita Prefecture. Seven populations collected from strawberry and tomato fields were tested for toxicity to 13 insecticides (acetamiprid, imidacloprid, clothianidin, dinotefuran, thiacloprid, nitenpyram, emamectin benzoate, chlorfenapyr, spinosad, tolfenpyrad, pymetrozine, pyridaben, and flonicamid), using the leaf-dipping method. Acetamiprid showed reduced mortality to both adults (mortality, 24.1 to 55.1%; LC50, 102.3 to 483.3 ppm) and larvae (mortality, 53.8% and 57.4%;LC50, 97.0 and 85.9 ppm). However, the other 12 insecticides showed high mortality (72.8 to 100%). These results provide the first evidence of a decline in susceptibility to acetamiprid in both adults and larvae of T. vaporariorum.