The olive leaf moth (OLM), Palpita unionalis (Hübner) (Lepidoptera: Pyralidae), poses a significant threat to olive cultivation. This study focused on isolating protease-producing bacteria from moribund field strains of P. unionalis larvae and assessing their larvicidal efficacy against laboratory strains through estimated LC30, LC50, and LC90 values. Additionally, the long-lasting impacts of LC50 values on pupal and adult stages were evaluated. Three entomopathogenic bacteria, Bacillus amyloliquefaciens, Pseudomonas putida, and Bacillus subtilis, were isolated. The larvicidal efficacies of these isolates varied, as B. subtilis exhibiting greater efficacy at LC30 and LC50 values, while P. putida showed the most potent effect at the LC90 value. Conversely, B. amyloliquefaciens demonstrated the lowest larvicidal potentialities at LC50 and LC90 values, with P. putida being the least effective at the LC30 value. The toxicity regression lines indicated increased larval lethality with each unit increase in concentration, as evidenced by the positive slope values. Chi-square (χ2) values suggested a better fit and supported the reliability of the estimated lethal concentrations. Exposure to LC50 values s resulted in significant elongation of larval duration and reduction in weight, whereas pupal lifespan, adult emergence, and sex ratio showed non-significant differences compared to untreated controls. The study highlights the promising role of these biological candidates in pest control programs as eco-friendly alternatives, potentially enhancing safe plant production. The varied larvicidal efficacies of the bacterial isolates, along with their proteolytic capabilities, underscore their potential as biocontrol pathogens against OLM, contributing to sustainable agricultural practices.

中文翻译：

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天然蛋白酶产生细菌分离株对橄榄叶蛾、Palpita unionalis (Hübner)（鳞翅目：Pyralidae）的生物防治功效

橄榄叶蛾 (OLM)、Palpita unionalis (Hübner)（鳞翅目：Pyralidae）对橄榄种植构成重大威胁。本研究的重点是从垂死的 P. unionalis 幼虫现场菌株中分离出产生蛋白酶的细菌，并通过估计的 LC30、LC50 和 LC90 值评估其对实验室菌株的杀幼虫功效。此外，还评估了 LC50 值对蛹和成虫阶段的长期影响。分离出三种昆虫病原菌：解淀粉芽孢杆菌、恶臭假单胞菌和枯草芽孢杆菌。这些分离株的杀幼虫功效各不相同，枯草芽孢杆菌在 LC30 和 LC50 值下表现出更强的功效，而恶臭假单胞菌在 LC90 值下表现出最有效的效果。相反，解淀粉芽孢杆菌在 LC50 和 LC90 值时表现出最低的杀幼虫潜力，恶臭假单胞菌在 LC30 值时效果最差。毒性回归线表明，随着浓度每增加一个单位，幼虫致死率增加，如正斜率值所证明。卡方 (χ2) 值表明更好的拟合并支持估计致死浓度的可靠性。暴露于 LC50 值导致幼虫持续时间显着延长和体重减轻，而与未处理的对照相比，蛹寿命、成虫羽化和性别比例显示出非显着差异。该研究强调了这些生物候选物作为生态友好的替代品在害虫防治计划中的前景广阔的作用，有可能提高植物的安全生产。细菌分离株具有不同的杀幼虫功效及其蛋白水解能力，强调了它们作为 OLM 生物防治病原体的潜力，有助于可持续农业实践。