四種殺蟲劑對大黑星龜金花蟲（Aspidomorpha Miliaris Fab.）幼蟲之毒效

Abstract

This study was conducted to determine the toxicity of Cartap, Chlorpyrifos, Imidacloprid and Abamectin toward Aspidomorpha miliaris larvae at various dilutions. The results showed that, 72 hours after treatment, 1000X dilutions of Cartap caused 97-100% mortality towards 1-5 instars larvae with no significant difference. At 2000x dilution, the mortalities toward 1-5 instar larvae were 47, 69, 81, 81 and 77%, respectively. Chlorpyrifos caused 100% mortality toward 1-5 instars larvae at the dilutions of 1000 and 2000x. At 5000x dilution, the mortalities of 1-4 instars larvae were 100% and 78% for fifth instar larvae. At dilution of 1000-10000x, the mortalities of Imidacloprid toward 1-5 instars larvae were 98~100%. At 15000x dilution, the mortalities towards 1-2 instars larvae were 99%; and 3-5 instars larvae were 84, 70 and 60%. At 1000-5000x dilution, the mortalities of Abamectin towards 1-5 instars larvae were 100%. At 10000-20000x dilution, the mortalities of 1-3 instar were 100%; for fourth instar larvae were 92, 97 and 38%. The mortalities of fifth instar larvae were 14, 14 and 8%. Toxicity of the tested pesticides was decreased with the increasing dilution rate. At the same dilution and the same instar larva, the efficacy had a tendency of Imidacloprid ＞ Abamectin ＞ Chlorpyrifos ＞ Cartap. Our suggestion of controlling A. miliaris is that: (1) Cartap at dilution 1000x is able to control all the five larval stage; (2) Chlorpyrifos at dilution of 1000 and 2000x are able to control all the five larval stage; at dilution of 5000x is able to control first to fourth instar larvae; (3) Imidacloprid at dilution of 1000-10000x are able to control all the five larval stage; (4) Abamectin at dilution of 1000-5000x are able to control all the five larval stage.