Abstract
The longhorn beetle, Apriona japonica, damages various broad-leaved trees. In a mixed forest of Robinia pseudoacacia and Celtis sinensis at Uchinada, Ishikawa Prefecture, barkfeeding adults are thought to attack C. sinensis primarily and to deposit eggs mainly on R. pseudoacacia. In order to verify the utility of fenitrothion-spraying to control A. japonica adults, I sprayed the branches of C. sinensis trees with 4.4% fenitrothion twice in the field, just before the occurrence of A. japonica adults and three weeks later. A. japonica adults were killed continuously throughout the period that they occurred on C. sinensis trees. I reared A. japonica adults in the laboratory on C. sinensis branches that were sprayed with 0.44% fenitrothion once and/or twice at a three-week interval. All adults were killed within three days when they fed on the branches sprayed once 1~4 weeks and those sprayed twice 4~6 weeks before the experiments, respectively. These results suggest that spraying fenitrothion should be effective in the management of A. japonica adults and that spraying of 0.44% fenitrothion twice at a 3 week interval can kill nearly 100% of adults over a period of nine weeks.
