The Colorado potato beetle (CPB) Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) is one of the most damaging pests of potatoes all over the world as well as in Turkey. Both adults and larvae of this pest feed on the foliage of potatoes, and often cause complete defoliation of potato plants, with considerable yield losses of up to 60%. Chemical control of this pest has induced the selection of resistant CPB populations and negative environmental impact. The aim of the present study was to evaluate the pathogenicity of 14 Turkish isolates of Beauveria bassiana (Balsamo) Vuillemin (Deuteromycota: Hyphomycetes) against different stages of CPB under laboratory conditions. All isolates were tested as conidial suspensions of (1 × 107 conidia/ml), using spray method. The results from pathogenicity assays showed that virulence of tested isolates was variable, and mortality increased with the time of exposure. The highest mortality was seen in larvae of CPB; however, young larvae (1st and 2nd instars) were more susceptible to fungal isolates than older ones (3rd and 4th instars). Four isolates (BbDm-1, BbDs-2, BbMg-2, and BbMp-1) were more pathogenic than others against L. decemlineata, causing mortalities between 96.7 and 100% in the 2 youngest larval instars, respectively, between 91.7 and 96.7% in the 2 oldest larval instars, respectively, and between 93.3 and 96.7% in 0–48-h-old adults, respectively, 9 days post treatment. Furthermore, these 4 isolates had the most potent egg-hatching inhibitory effects (66.7–90%). The results of molecular phylogenetic analyses based on the ITS region sequence indicated that all tested B. bassiana isolates showed a high similarity (99%) with other B. bassiana isolates in GenBank. Results suggested that the 4 B. bassiana isolates were highly virulence and had the potential for biological control of CPB. Further tests under field conditions are recommended to validate the laboratory results.

中文翻译：

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球孢白僵菌（Balveria bassiana（Balsamo）Vuillemin（Deuteromycota：Hyphomycetes）的土著分离株对科罗拉多马铃薯甲虫Leptinotarsa decemlineata（Say）（鞘翅目：菊科）的功效

科罗拉多马铃薯甲虫（CPB）Leptinotarsa decemlineata（Say）（鞘翅目：金眼科）是全世界以及土耳其最有害的马铃薯害虫之一。该害虫的成虫和幼虫都以马铃薯的叶子为食，并经常导致马铃薯植株完全脱叶，产量损失高达60％。化学控制该害虫已导致选择抗性CPB种群，并对环境造成负面影响。本研究的目的是评估在实验室条件下14种土耳其白僵菌（Balsamo）Vuillemin（Deuteromycota：Hyphomycetes）分离株对CPB的致病性。使用喷雾法将所有分离物测试为（1×107分生孢子/ ml）的分生孢子悬液。致病性分析的结果表明，测试菌株的毒力是可变的，并且死亡率随着接触时间的增加而增加。在CPB的幼虫中死亡率最高。然而，幼虫（第一龄和第二龄）比年龄较大的幼虫（第三龄和第四龄）更容易分离真菌。四个分离株（BbDm-1，BbDs-2，BbMg-2和BbMp-1）对落叶松乳杆菌的致病性比其他分离株高，分别在2个最年轻的幼虫龄中致死率分别为96.7和100％，分别在91.7和96.7之间治疗后第9天，分别是2个最老的幼虫龄期的％和0-48 h的成年幼虫的93.3％和96.7％之间。此外，这4种分离物具有最强的卵孵化抑制作用（66.7–90％）。基于ITS区域序列的分子系统发育分析结果表明，所有测试的球茎白僵菌菌株均与GenBank中的其他球茎白僵菌菌株具有高度相似性（99％）。结果表明，4个球孢杆菌分离株具有高毒力，具有对CPB进行生物防治的潜力。建议在野外条件下进行进一步测试以验证实验室结果。