Development of Insecticide Resistance of Brown Planthoppers in Central Taiwan

Shun-Cheng Wang ； Te-Yeh Ku

《中華昆蟲》 4卷2期 (1984/09) Pp. ap15+131-138

https://doi.org/10.6660/TESFE.1984022

摘要

Since 1976, the toxicity of 14 insecticides to brown planthoppers collected from rice field in central Taiwan has been periodically monitored by a residual film method. LC_(50) values separately obtained in 1977-1983 and in 1976 were compared to determine if insecticide resistance had developed during these years as a basis upon which to make a reference to changes in the resistance of brown planthoppers during the corresponding period. The resistance of brown planthoppers to the test insecticides remained relatively unchanged until 1979. In 1980, threir relative resistance (LC_(50) value compared with that in 1976) to carbaryl and carbofuran increased 8.4- and 14.8-fold, respectively. Since 1979, their resistance to most organophosphorus insecticides has shown a gradual decrease with he exception of malathion. In 1980, the level of their resistance to malathion and monocrotophos reached a record high. In 1981 and 1982 tests, their resistance to both carbamates and organophosphates decreased gradually except methomyl and malathion. An unusual high-level resistance of brown planthoppers to the 14 test insecticides was found again in 1983, however. To detect the local difference of resistance, a max./min. level of LC_(50) was employed in 1982. Results showed that it varied 2.4- to 15.5-fold in six localities for four of the insecticides tested. In 1983, a similar detection also revealed a 2.4- to 6.2-fold variability. The evidence suggested a local difference. Brown planthoppers were collected in September, October and November of 1983 in six different areas of central Taiwan to measure the monthly changes of insecticide resistance. The monthly changes varied significantly, suggesting that migration was one of the factors that affecting the brown planthoppers resistance.