The two-spotted spider mite, Tetranychus urticae (Koch) (Acari: Tetranychidae), is a widely distributed plant-feeding pest that causes significant yield losses in a wide range of crops. Newly developed or improved environmentally friendly biocontrol agents serve as an alternative to traditional pest control tools. Experiment of the effects of 2 local fungal isolates of Beauveria bassiana (BGF14 and BCA32) was carried out against T. urticae under laboratory conditions. Both tested isolates had lethal effect in a short time after application, and this effect increased as time progressed. BGF14 and BCA32 isolates caused T. urticae mortality rates ranging from 25.88 to 61.92 and 32.36 to 62.03% when applied at the concentrations between 1×105 and 1×108 conidia/ml, respectively. According to the Probit analysis performed on the effect of fungi on T. urticae adults, the LC50 values of BGF14 and BCA32 isolates on the 7th day after inoculation were 2.6×106 and 6.3×104 conidia/ml, respectively, and the LT50 values for both fungi applied at a concentration of 108 conidia/ml were 2.14 and 2.23 days, respectively. The 2 isolates of B. bassiana (BGF14 and BCA32) had the potentials to suppress T. urticae population and can be recommended as promising biocontrol agent candidates for control of T. urticae.

中文翻译：

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球孢白僵菌Vuillemin的本地分离株对二斑叶螨Tetranychus urticae（Koch）（Acari：Tetranychidae）的影响

有两个斑点的红蜘蛛Tetranychus urticae（Koch）（Acari：Tetranychidae）是一种分布广泛的植物性食性害虫，在许多作物上造成明显的单产下降。新开发或改良的环境友好型生物防治剂可以替代传统的害虫防治工具。在实验室条件下，对球孢白僵菌的两种局部真菌分离物（BGF14和BCA32）进行了抗荨麻疹的实验。两种测试过的分离株在施用后的短时间内均具有致死作用，并且这种作用随着时间的推移而增加。当以1×105至1×108分生孢子/ ml的浓度施用BGF14和BCA32分离株时，荨麻疹的死亡率分别为25.88％至61.92％和32.36％至62.03％。根据Probit分析，对真菌对T的影响进行了分析。荨麻科成虫，接种后第7天BGF14和BCA32分离株的LC50值分别为2.6×106和6.3×104分生孢子/ ml，两种真菌的浓度为108分生孢子/ ml时的LT50值为2.14和分别为2.23天。球孢杆菌的2种分离株（BGF14和BCA32）具有抑制荨麻疹种群的潜力，可以推荐作为控制荨麻疹的有前途的生物防治剂。