四种杀虫药剂对麦长管蚜、七星瓢虫及燕麦茧蜂的毒力比较

室内应用虫体浸渍及定量喷雾毒力法测定 LC_(50)结果表明;四种杀虫药剂对麦长管蚜(Sitobion avenea(F))的毒力下降顺序为抗蚜威、杀灭菊酯、乐果、丙体六六六;对七星甄虫(Coccinella septempunctata L.)四个虫期的毒力表现趋势并不完全一致,但一般还可以看出抗药力下降顺序为卵、蛹、成虫、幼虫。通过七星瓢虫与麦长管蚜的毒效比可以看出抗蚜威对七星瓢虫极安全,毒效比最低是成虫也达到5877.3,其次是杀灭菊酯最低的是幼虫8.38,乐果最低的是成虫1.94,而丙体666最低的是幼虫只有0.54,极不安全,氧乐果与乐果差剐不大。对僵蚜内燕麦茧蜂(Aphidius avenea Haliday)蛹的毒力,除丙体666(LC_(50)=223.8)外都很低,此使用浓度高及低各9倍,蛹羽化率差异不显著。因此用最高浓度与麦蚜 LC_(50)的毒效比值,除丙体666为2.14外,其余都大于147,是很安全的。对燕麦茧蜂成虫,毒力下降顺序是乐果、丙体666、抗蚜威、杀灭菊酯。因此燕麦茧蜂成虫 LC_(50)与麦蚜 LC_(50)的毒效比最低是丙体666和乐果,都低于0.042,极不安全,最高...

TOXICITY OF FOUR INSECTICIDES TO CEREAL APHID(sitoion avenea(F.)),ITS PREDATOR SEVEN SPOT LADYBIRD(coccinella septempunctatal.)andaphidiid pararsite(aphidiusaverea halday)

Laboratory tests showed that the LC50s of pirimicarb,fenvalerate, dimethoate,and r-BHC to cereal aphid were 0.99,3.03,6.53,and 109.2 ppm respectively.while the ascenting order of its toxicitys to the four stsges of seven spot ladybird were usually egg,pupa,adult and larva. The selective ratio(SR)(natural enemies LC50/pest LC50)of the four insecticides to four stages of seven spot ladybird VS viviparous fem- ale of cereal aphid exhibited that pirimicarb was the highest,(all over 5877),therefore it was extrem...