Selecting entomopathogenic fungal isolates with resilience to environmental stresses, optimal mass production characteristics, and with high virulence to target pests favors the development of mycopesticides. A case in point, Cordyceps (= Isaria) javanica has been extensively investigated for non-chemical control of whiteflies worldwide. We phylogenetically characterized 11 native C. javanica isolates from Northeastern and Central Brazil. These isolates were screened for tolerance to heat-shock, UV-B radiation, osmotic and oxidative stresses, as well as conidial production on cereal grain and insecticidal activity against the whitefly Bemisia tabaci (MEAM 1) in the laboratory. All isolates were pathogenic to whiteflies and significant (3-fold) differences in median lethal concentration were observed among isolates. Furthermore, pronounced differences among isolates were found for stress factors and conidial production. Using principal component analysis, our results highlighted three major clusters formed by isolates (i) resistant to osmotic and oxidative stress, (ii) resilient to UV-B, and (iii) with high virulence, conidial production and heat tolerance. Overall, isolate CG1228 performed best based on multi-stress resistance, mass production and virulence attributes in the laboratory. This study highlights the importance of exploring natural variation in entomopathogenic fungi for selection of appropriate isolates for effective biocontrol of insect pests coupled with mass production characteristics and abiotic stress tolerances.

选择对环境压力具有抵抗力，最佳的批量生产特性，对目标有害生物具有高毒力的昆虫致病性真菌分离株有利于抗真菌农药的开发。举个典型的例子，虫草（= Isaria）javanica已在世界范围内广泛地用于粉虱的非化学防治。我们从巴西东北和中部地区的11种本地C. javanica菌系进行了系统发育分析。筛选了这些分离物的耐热性，UV-B辐射，渗透压和氧化胁迫的耐受性，以及谷物的分生孢子产生和对粉虱烟粉虱的杀虫活性。（MEAM 1）在实验室中。所有分离株对粉虱均具有致病性，并且在分离株之间观察到中值致死浓度显着（3倍）差异。此外，发现分离株之间在胁迫因子和分生孢子产生方面存在明显差异。使用主成分分析，我们的结果突出显示了由分离物形成的三个主要簇（i）具有抗渗透性和氧化性；（ii）具有抗UV-B的能力；（iii）具有高毒力，分生孢子产生性和耐热性。总体而言，基于实验室中的多抗性，批量生产和毒力属性，分离株CG1228表现最佳。