苜蓿蚜药剂防治试验

使用九种药剂进行蚜虫的毒力测定，并计算ＬＣ５０值。结果：浓度值域在０．０８２％￣２．８３％之间，相差３６．４倍，表明各药剂对蚜虫毒力差异很大。田间药剂防治试验结果，抗蚜威，菊马，敌杀死，杀灭菌酯在喷雾浓度分别为３５００￣４５００倍、３５００￣４０００倍、３０００￣４０００倍、２０００￣３０００倍时，防效最佳，依次为８８．６％￣９１．２％，８７．６％￣９０．７％、８６．７％￣８７．２％和８５．２％￣

A Experiment on Chemical Control of Black Bean Aphid (Aphis craccivora Koch)

The median lethal concentrations (LC50 ) of 9 pesticides obtained after their toxicities were tested. Minimum and maximum were from 0.082% to 2.83% and differed 36.4 times between them. This showed that the toxicity was very different in various pesticides. Through field trial for control of Aphis craccivora, the following chemicals were screened primarily: pirimicarb, juma emulsion (a compound formulation of fenvalerate & malathion) ,decamethrin and fenvalerate. Their suitable concentrations for field spraying are 3 500 - 4 500,3 500-4 000,3 000-4000 and 2000-3000 times, respectively. The corresponding control effects are 88.6% - 91.2% ,87.6% - 90.7% ,86.7 - 87.2% and 85.2% -86.9% .The experimental result also indicated that control effect looked better obviously when those pes-licides were used (according to above- mentioned concentration, each pesticide spraying dilution 66.7kg per Chinese mu) in later period of flowered broadbean. The paper writer suggest these chemicals are wor-thy of application in practice.