印楝素农药与虫生真菌混用防治红树林鳞翅目害虫

Combining azadirachtin-based insecticides with entomopathogenous fungi control Lepidopteron pests on mangroves

采用2种印楝素农药1%印楝素苦参碱乳油和0.3%印楝素乳油,以及2个虫生真菌绿僵菌菌株和白僵菌菌株对桐花长卷蛾、棉古毒蛾和广州小斑螟等3种红树林叶面和种子害虫的室内毒力测定结果表明,两种印楝素农药的单剂(500～1000倍)和与虫生真菌的复配剂(700倍),均对害虫有较强的毒性,一周内害虫死亡率达78.6～100%。两种印楝素农药与虫生真菌混合使用均比各自单独使用的杀虫效果好,其中与虫生真菌的复配剂700倍液的杀虫最快,效果最好,第3天柑橘长卷蛾和广州小斑螟的死亡率达100%,棉古毒蛾的死亡率达93.3%。应用1%印楝素苦参碱乳油和0.3%印楝素乳油与绿僵菌和白僵菌的复配剂500倍液进行林间防治危害桐花树的柑橘长卷蛾的试验,防治效果达65.4%～100%,该复配剂具有内吸传导作用、高效、低毒和安全等优点,值得大力推广应用。

A laboratory bioassay was carried out on two azadirachtin-based insecticides and their mixtures with entomopathogenous fimgi against Lepidoteron pests on mangroves. The results showed that Azadirachtin-matrine 1% EC and Azadirachtin 0.3% EC and their mixtures with one strain of Metarhizium anisopliae （Ma） and one strain of Beauveria bassiana （Bb） were very virulent to mangroves insect pests including Homona coffeari, Oligochroa cantoonella and Orgyia postica, and about 78.6- 100% of mortality was caused within one week with a diluted solution of 500 to 1000 times of single insecticide or a dilution of 700 times of insecticides mixed with a concentration of 1×10^6 sporesomLl of Ma＆Bb. The mixture of both Azadirachtin-based insecticides and Ma＆Bb was more effective to kill insects than single agent. The mixture of both insecticides at a dilution of 700 times and Ma＆Bb at a concentration of 1×10^6 spores ·mL^-1 caused 100% of mortality to Homona coffeari and 93.3% of mortality to Orgyia postica 3 days after treatment. The application of the mixture of both insecticides at a dilution of 500 times and Ma＆Bb at a concentration of 1×10^6 spores ·mL^-1 was successfully to control Homona coffeari on Aegiceras corniculatum in the field, with a mortality of 65.4-- 100%. It is suggested that the mixture can be extended largely to control Lepidopteron pests on mangroves due to its systemic effect, high virulence, low toxicity and environmental safety.