安徽虫瘟霉对桃蚜的生物测定与时间-剂量效应分析

用“孢子浴”法将人工培养的安徽虫瘟霉（Ｚｏｐｈｔｈｏｒａａｎｈｕｉｅｎｓｉｓ）对桃蚜（Ｍｙｚｕｓｐｅｒｓｉ ｃａｅ）接种而进行定量生物测定（１８℃，光周期为Ｌ∶Ｄ１２∶１２），包括１０个剂量（１．５～１９７．７个分生孢子／ｍｍ２），每剂量处理蚜虫６４～１２０头，逐日观察记载死亡数至第７ｄ。接种后第３ｄ在高剂量处理中始见少量死蚜，第４～６ｄ为死蚜盛期。所获数据很好地拟合时间 剂量 死亡率模型，由模型参数估计出该菌作用于桃蚜的时间效应随剂量增大而减小，在３７．１～１９７．７个分生孢子／ｍｍ２的剂量范围内ＬＴ５０值为４．５～６．７ｄ；剂量效应在接种后随时间递减，第５～７ｄ的ＬＤ５０分别为８６．８、４３．７和３４．１个分生孢子／ｍｍ２。结果表明，安徽虫瘟霉是一种较为理想的杀蚜微生物，在寄主体内的潜伏期为４～５ｄ。

THE TIME DOSE EFFECT OF THE ENTOMOPHTHORALEAN FUNGUS, ZOOPHTHORA ANHUIENSIS AGAINST THE GREEN PEACH APHID, MYZUS PERSICAE, IN BIOASSAY

The entomophthoralean fungus, Zoophthora anhuiensis , was bioassayed on the green peach aphid, Myzus percisae in a growth chamber at the regime of 18℃ and 1212 (L∶D). The aphids with detached leaves of the Chinese cabbage were exposed to the spore shower of the fungal inocula produced in vitro for 1～30 min, resulting in 10 doses (1.5～197.7 conidia per square milliliter) with each for 64～120 aphids. Based on daily observations, the visible deaths attributed to the spore shower did not occur until day 3 after the exposure but most of the deaths occurred on days 4～6. The resulting data fit well to the time dose mortality model, generating the parameters for use in estimation of lethal dose (LD 50 ) and time length (LT 50 ) effects. The estimates of LT 50 ’s ranged from 4.5 to 6.7 d at the doses of 37.1～197.7 conidia per square milliliter, decreasing with the increasing doses. The LD 50 ’s were 86.8, 43.7, and 34.1 conidia per square milliliter from day 5 to day 7 after the exposure, respectively. The results showed that Z. anhuiensis was a promising aphidicidal fungal pathogen with a latent period of 4～5 d in host.