Lord Jeffrey C
Grain Marketing and Production Research Center, USDA-ARS, 1515 College Avenue, Manhattan, KS 66502, USA.
J Econ Entomol. 2007 Aug;100(4):1071-4. doi: 10.1603/0022-0493(2007)100[1071:eeobbf]2.0.co;2.
Red flour beetle, Tribolium castaneum (Herbst), is a major pest of stored and processed grains that is tolerant of Beauveria bassiana (Balsamo) Vuillemin under most conditions. Laboratory assays demonstrated that desiccating conditions improved the efficacy of the fungus. For T. castaneum larvae exposed to B. bassiana at different vapor pressure deficits (VPDs), the LC50 potency ratios were 2.3 for 2.42 kPa and 3.9 for 3.31 kPa compared with 1.06 kPa. There were significant effects of moisture on B. bassiana-associated mortality even with brief exposure to low VPD before or at the beginning of exposure to fungus. When T. castaneum larvae were held at 3.31 kPa 1 d before exposure to B. bassiana and/or in the first 1 or 2 d of exposure to the fungus, there was significantly greater mortality for all of the low moisture treatments than occurred with continuous incubation at 1.06 kPa. B. bassiana efficacy for adult T. castaneum was significantly better for VPDs of 3.56 or 3.78 than 1.06 kPa. Weight gain over 4 d of incubation with moisture held constant was significantly less at a VDP of 3.31 kPa than at 1.87 or 1.06 kPa. Treatment with fungus did not affect weight gain significantly. There was no significant difference in larval water content among treatments.
赤拟谷盗（Tribolium castaneum (Herbst)）是储存谷物和加工谷物的主要害虫，在大多数情况下对球孢白僵菌（Beauveria bassiana (Balsamo) Vuillemin）具有耐受性。实验室分析表明，干燥条件可提高该真菌的效力。对于在不同蒸汽压亏缺（VPD）下暴露于球孢白僵菌的赤拟谷盗幼虫，与1.06 kPa相比，在2.42 kPa时的LC50效力比为2.3，在3.31 kPa时为3.9。即使在接触真菌之前或开始时短暂暴露于低VPD，湿度对与球孢白僵菌相关的死亡率也有显著影响。当赤拟谷盗幼虫在接触球孢白僵菌前1天保持在3.31 kPa和/或在接触真菌的前1或2天保持在该压力下时，所有低湿度处理的死亡率均显著高于在1.06 kPa持续培养的情况。对于成年赤拟谷盗，3.56或3.78 kPa的VPD下球孢白僵菌的效力明显优于1.06 kPa。在湿度保持恒定的情况下培养4天，3.31 kPa的VDP下体重增加明显低于1.87或1.06 kPa。用真菌处理对体重增加没有显著影响。各处理间幼虫含水量无显著差异。
