The genus Beauveria is frequently used as a mycoinsecticides in many countries to control insect pests in agriculture, it is being very effective against the fall webworm, Hyphantria cunea (Durry) (Lepidoptera: Erebidae), which is a pest of trees in forests and orchards. Multiple abiotic factors during fungal growth are well known to influence mycelial growth and several physiological adaptations in the conidia produced. In this study, the pathogenicity of the Beauveria bassiana strains Bb10331 and Bb7725 against H. cunea was evaluated. Peptone potato dextrose agar (PPDA) was used as the medium and colony diameter, conidiation capacity, conidial germination rate were directly affected by relative humidity (RH), illumination, and the ambient pH. The LC50 values of Bb10331 and Bb7725 to H. cunea were 4.72 × 106 and 3.28 × 106 conidia·ml−1, respectively, after 120 h post treatments, while their corresponding LT50 values were 71.13 and 74.54 h at the concentration of 1 × 108 conidia/ml. The Bb7725 had a conidial germination rate than did Bb10331 at the same RH. The two strains grew faster under a dark:light (D:L) photoperiod of 12:12 h, and this particular light condition was also most suitable for their conidia production. The optimum pH for the growth and conidiation of the two strains was approximately 7.0. Both strains are promising for pest control, possessing effective virulence against H. cunea, but this is slightly stronger in Bb7725 than Bb10331. The values of abiotic factors apt to promote the biological properties of each B. bassiana were different.

中文翻译：

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关于两种球孢白僵菌对秋螟、Hyphantria cunea (Durry) (Lepidoptera: Erebidae)、幼虫的毒力及其与不同非生物因素相关的生物学特性

白僵菌属在许多国家经常被用作杀真菌剂来控制农业害虫，它对秋季螟虫非常有效，Hyphantria cunea (Durry) (Lepidoptera: Erebidae)，这是一种森林和果园中的树木害虫. 众所周知，真菌生长过程中的多种非生物因素会影响产生的分生孢子中的菌丝生长和几种生理适应性。在本研究中，评估了球孢白僵菌 Bb10331 和 Bb7725 对楔形孢霉的致病性。以蛋白胨马铃薯葡萄糖琼脂（PPDA）为培养基，菌落直径、分生孢子能力、分生孢子萌发率直接受相对湿度（RH）、光照和环境pH值影响。Bb10331 和 Bb7725 对 H. cunea 的 LC50 值为 4.72 × 106 和 3.28 × 106 分生孢子·ml−1，分别在处理后 120 h 后，在 1 × 108 分生孢子/ml 的浓度下，它们相应的 LT50 值为 71.13 和 74.54 h。在相同的相对湿度下，Bb7725 的分生孢子萌发率高于 Bb10331。这两个菌株在 12:12 小时的暗:光 (D:L) 光周期下生长更快，这种特殊的光照条件也最适合它们的分生孢子生产。两种菌株生长和分生孢子的最适 pH 值约为 7.0。这两种菌株都有望用于害虫控制，对 H. cunea 具有有效的毒力，但 Bb7725 的毒力略强于 Bb10331。促进每种球孢菌生物学特性的非生物因子值不同。54 小时，浓度为 1 × 108 分生孢子/ml。在相同的相对湿度下，Bb7725 的分生孢子萌发率高于 Bb10331。这两个菌株在 12:12 小时的暗:光 (D:L) 光周期下生长更快，这种特殊的光照条件也最适合它们的分生孢子生产。两种菌株生长和分生孢子的最适 pH 值约为 7.0。这两种菌株都有望用于害虫控制，对 H. cunea 具有有效的毒力，但 Bb7725 的毒力略强于 Bb10331。促进每种球孢菌生物学特性的非生物因子值不同。54 小时，浓度为 1 × 108 分生孢子/ml。在相同的相对湿度下，Bb7725 的分生孢子萌发率高于 Bb10331。这两个菌株在 12:12 小时的暗:光 (D:L) 光周期下生长更快，这种特殊的光照条件也最适合它们的分生孢子生产。两种菌株生长和分生孢子的最适 pH 值约为 7.0。这两种菌株都有望用于害虫控制，对 H. cunea 具有有效的毒力，但 Bb7725 的毒力略强于 Bb10331。促进每种球孢菌生物学特性的非生物因子值不同。这种特殊的光照条件也最适合它们的分生孢子生产。两种菌株生长和分生孢子的最适 pH 值约为 7.0。这两种菌株都有望用于害虫控制，对 H. cunea 具有有效的毒力，但 Bb7725 的毒力略强于 Bb10331。促进每种球孢菌生物学特性的非生物因子值不同。这种特殊的光照条件也最适合它们的分生孢子生产。两种菌株生长和分生孢子的最适 pH 值约为 7.0。这两种菌株都有望用于害虫控制，对 H. cunea 具有有效的毒力，但 Bb7725 的毒力略强于 Bb10331。促进每种球孢菌生物学特性的非生物因子值不同。