Abstract
Population densities of the thrips, Frankliniella occidentalis Pergande (Fo) and F. intosa (Trybom) on tomato flowers were suppressed at low level by the flower application of 4-CPA (p-chlorophenoxyacetic acid) 15 ppm added spinosad 50 ppm at 3 to 4 days' intervals during flowering period. White swelling spot on fruits was reduced greatly by the flower application. The total amount of the flower application was about 1/100 of the custom one. Spinosin residue on mature fruits by the flower application was fewer than by the custom one. The control effect for white swelling spot by the flower application of 8 insecticides were compared by releasing Fo adults. As a result, spinosad 50 ppm, tolfenpyrad 150 ppm and fipronil 22 ppm were highly effective, while acephate 500 ppm, acrinathrin 30 ppm and chlorfenapyr 50 ppm were moderate, and malathion 250 ppm and acetamiprid 100 ppm were non-effective.
