The interaction between Isaria fumosorosea and short -term heat treatment on 3rd instar larvae of Plutella xylostella was investigated. The results showed that the interaction varied with the differences of the heat duration, conidia concentration and the processing sequence. When the larvae were pretreated with the conidia before the short - term heat treatment of different time at the concentration of 1 × 10 and 1 × 10 conidia/mL, the interaction effect resulted in antagonism at all treatment; While at the concentration of 1 × 107 conidia/mL and the heat treatment at 35℃ for 2 hours, the interaction effect resulted in antagonism, but in the trials for 4 h and 8 ℃, addition were observed. At the concentration of 1 × 105 conidia/mL and the larvae were pretreated with the short - term heat treatment at 35℃ for 2 h, the interaction effect resulted in antagonism; While at the concentration of 1 × 107 conidia/mL and the larvae were pretreated with the short - term heat treatment at 35°C for 8 h, potentiation was observed; All the other treatment were addition, in conclusion, on a hot summer day, spraying the I.fumosorosea that the conidia concentration of 1 × 10 conidia/mL is the optimal recommended scheme for controlling P. xylostella toward evening. Results indicated that the interaction assessment procedure might be adopted in Hormesis study.%研究了玫烟色棒束孢与短期35℃高温对小菜蛾3龄幼虫的联合作用,结果表明:短期高温及玫烟色棒束孢对小菜蛾的联合作用随高温持续时间、玫烟色棒束孢菌液浓度及两者处理顺序不同而不同.在菌液浓度为1×105、1×106孢子/mL预处理后,再经短期35℃高温处理不同时间条件下,其联合作用均表现为拮抗作用;在菌液浓度为1×107孢子/mL预处理后,再经短期35℃高温处理2h,则表现为拮抗作用,4和8h时则均表现为相加作用.在35℃高温预处理2h和菌液浓度为1×105孢子/mL的条件下,表现为拮抗作用;在35℃高温预处理8h和菌液浓度为1×10 7孢子/mL的条件下,表现为协同作用;其余高温预处理与不同孢子浓度组合对小菜蛾的毒力均表现为相加作用.综上所述,在夏季高温天气,田间推荐防治小菜蛾的最佳方案为:傍晚时分,喷施菌液浓度为1×10 7孢子/mL.研究结果初步说明,联合作用评价方法可以用于Hormesis效应研究.
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