苏云金芽胞杆菌HA和HD对黄曲条跳甲成虫的毒力分析

Toxicity analysis of Bacillus thuringiensis HA and HD against Phyllotreta striolata adults

黄曲条跳甲Phyllotreta striolata(Fabricius)是为害十字花科蔬菜的世界性害虫之一。为了探究苏云金芽胞杆菌HA和HD对黄曲条跳甲成虫的防治潜力,本研究测定了苏云金芽胞杆菌HA和HD菌株对黄曲条跳甲成虫的毒力,以及对其谷胱甘肽-S-转移酶(GST)活性和中肠组织形态的影响。结果表明:Bt-HA和Bt-HD均对黄曲条跳甲成虫有杀虫活性,LC_(50)分别为4.01×10^(8)CFU/mL和1.17×10^(8)CFU/mL。菌株Bt-HD处理组的GST酶活性高于对照组和菌株Bt-HA处理组。菌株Bt-HA处理黄曲条跳甲成虫14 d后,中肠微绒毛肿胀脱落;菌株Bt-HD处理黄曲条跳甲成虫4 d后中肠微绒毛开始疏松脱落,14 d后中肠柱状细胞底膜变形脱落。综上所述,苏云金芽胞杆菌HD对黄曲条跳甲成虫的毒力更强,是防治黄曲条跳甲成虫的优势菌株,其杀虫机理值得深入研究。

The Striped flea beetle,Phyllotreta striolata(Fabricius),is one of the most destructive pests of cruciferous vegetables worldwide.To explore prevention potential of Bacillus thuringiensis HA and HD on P.striolata adults,bioassays,glutathione S-transferase(GST)enzyme activity and histopathological analysis of midgut epithelium of P.striolata adults were conducted.The results showed that the LC_(50)values of Bt-HA and Bt-HD were 4.01×10^(8)CFU/mL and 1.17×10^(8)CFU/mL respectively.GST enzyme activity in the Bt-HD treatment group was higher than that in the control group and the Bt-HA treatment group.Histopathological analysis revealed the microvilli swelled and fell off after 14 days of treatment with Bt-HA,the microvilli began to loosen and fall off after 4 days of treatment with strain Bt-HD,and the basement membrane of columnar cells in the midgut began to deform and fall off after 14 days.In conclusion,Bt-HD is more virulent to adults of P.striolata than Bt-HA.The insecticidal mechanism of B.thuringiensis HD on P.striolata adults should be further investigated.