球孢白僵菌可湿性粉剂对马铃薯甲虫的防治效果

从受感染的马铃薯甲虫Leptinotarsa decemlineata（Say）分离出菌株1513,经鉴定为球孢白僵菌Beauveriabassiana（菌种保藏号为ACCC32222）。为了评价其对马铃薯甲虫的防治潜力,本研究测定了不同浓度白僵菌对不同龄期马铃薯甲虫幼虫的毒力作用。结果表明,在室温条件下（22～28℃）,处理9 d时1～2龄幼虫的僵虫率与孢子浓度成正比,其LC50为3.09×107孢子mL 1;处理8 d时,对3～4龄幼虫的LC50为9.92×107孢子mL 1;而孢子浓度为1×107孢子mL 1时,虫卵未受到明显的抑制。田间施菌2250 g hm 2时,在新疆新源县的防治效果较好,18 d时98.87%的虫体落地,地表僵虫率为53.91%;而在新疆尼勒克县,仅在土壤中发现僵虫,僵虫率为19.61%。

Effect of Beauveria bassiana Wettable Powder against Leptinotarsa decemlineata （Say）

The strain 1513 isolated from infected Leptinotarsa decemlineata was purified and identified to be Beauveria bassiana and conserved in agricultural culture collection of china（ACCC） with the number of ACCC32222.To evaluate its biocontrol potential,virulence of the isolate against different instar larvae of L.decemlineata was investigated under different spore concentrations.Results showed that when the temperature was 22 28 ℃,the cadaver rate of 1st 2nd instar larvae increased with the increase of spore concentration.The LC50 values of 9 days after treatment on 1st 2nd instar larvae and 8 days after treatment on 3rd 4th instar larvae of L.decemlineata were 3.09×107 conidia mL 1 and 9.92×107 conidia mL 1,respectively.Eggs of L.decemlineata were not inhibited when the spore concentration was 1×107 conidia mL 1.Field trials in Xinyuan of Xinjiang demonstrated that the mortality of L.decemlineata reached 98.87% when treated with B.bassiana wettable powder at about 2250 g ha 1 after 18 days,and cadaver rate on the earth surface was 53.91%.However,cadaver was only found in the soil with cadaver rate of 19.61% in Nileke of Xinjiang.