The tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a serious pest of solanaceous plant species, mainly Solanum lycopersicum L. The entomopathogenic fungi, an alternative to chemical insecticides, proved to be an efficient biocontrol agent in reducing pest population density. In the present study, an entomopathogenic fungus, Purpureocillium lilacinum isolated from soil was identified based on the morphological and molecular characteristics and its pathogenicity was tested against target pest. The micromorphological characters showed variations in growth pattern, shape and colour on different cultural media. For molecular analysis, a phylogenetic tree based on ITS/LSU and ITS/β-tubulin (benA) gene regions was constructed which revealed the isolate (FC18) as P. lilacinum (Thom) Luangsa-ard, Houbraken, Hywel-Jones and Samson (Family: Ophiocordycipitaceae). Further, the pathogenicity of P. lilacinum was tested using different spore concentrations (1 × 108, 1 × 107, 1 × 106, 1 × 105 and 1 × 104 spores/ml) on larval and pupal stages of T. absoluta, which showed a dose-dependent mortality. At the highest concentration (1 × 108 spores/ml), the mean mortality of 92.99, 83.05, 72.0% of second, third and fourth instar was observed, respectively. Pupal mortality also showed significant differences at different spore concentrations. Obtained results showed that the virulence of the indigenous strain of P. lilacinum on T. absoluta can be utilized in the field suppression of the pest as a potent biocontrol agent.

中文翻译：

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昆虫病原真菌Purpureocillium lilacinum的形态学和分子鉴定及其对Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)幼虫和蛹的毒力

番茄潜叶虫 Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) 是茄科植物物种（主要是 Solanum lycopersicum L）的严重害虫。昆虫病原真菌是化学杀虫剂的替代品，被证明是减少害虫种群的有效生物防治剂密度。在本研究中，基于形态和分子特征鉴定了从土壤中分离出的一种昆虫病原真菌Purpureocillium lilacinum，并对其对目标害虫的致病性进行了测试。微形态特征在不同培养基上表现出生长模式、形状和颜色的变化。对于分子分析，构建了基于 ITS/LSU 和 ITS/β-微管蛋白 (benA) 基因区域的系统发育树，其揭示分离物 (FC18) 为 P. lilacinum (Thom) Luangsa-ard, Houbraken, Hywel-Jones 和 Samson（科：蛇形虫科）。此外，使用不同的孢子浓度（1 × 108、1 × 107、1 × 106、1 × 105 和 1 × 104 孢子/ml）对绝对百合的幼虫和蛹阶段的 P. lilacinum 的致病性进行了测试，结果表明剂量依赖性死亡率。在最高浓度（1×108 孢子/ml）下，二龄、三龄和四龄的平均死亡率分别为 92.99、83.05、72.0%。蛹死亡率在不同孢子浓度下也显示出显着差异。获得的结果表明，P. lilacinum 本地菌株对 T. absoluta 的毒力可作为有效的生物防治剂用于田间抑制害虫。1 × 106, 1 × 105 和 1 × 104 孢子/ml）在 T. absoluta 的幼虫和蛹阶段，显示出剂量依赖性死亡率。在最高浓度（1×108 孢子/ml）下，二龄、三龄和四龄的平均死亡率分别为 92.99、83.05、72.0%。蛹死亡率在不同孢子浓度下也显示出显着差异。获得的结果表明，P. lilacinum 本地菌株对 T. absoluta 的毒力可作为有效的生物防治剂用于田间抑制害虫。1 × 106, 1 × 105 和 1 × 104 孢子/ml）在 T. absoluta 的幼虫和蛹阶段，显示出剂量依赖性死亡率。在最高浓度（1×108 孢子/ml）下，二龄、三龄和四龄的平均死亡率分别为 92.99、83.05、72.0%。蛹死亡率在不同孢子浓度下也显示出显着差异。获得的结果表明，P. lilacinum 本地菌株对 T. absoluta 的毒力可作为有效的生物防治剂用于田间抑制害虫。蛹死亡率在不同孢子浓度下也显示出显着差异。获得的结果表明，P. lilacinum 本地菌株对 T. absoluta 的毒力可作为有效的生物防治剂用于田间抑制害虫。蛹死亡率在不同孢子浓度下也显示出显着差异。获得的结果表明，P. lilacinum 本地菌株对 T. absoluta 的毒力可作为有效的生物防治剂用于田间抑制害虫。