The most dominant pest of date stored in Khuzestan Province is Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). In this study, the effects of Bacillus thuringiensis Kurstaki bacteria and Beauveria bassiana pathogenic fungi on the population dynamics of E. kuehniella date stock pest were investigated. To fulfill this, insectariums were kept in vitro at an average temperature of 27 ± 5 °C and a RH of 40 ± 5% for a duration of 6 months, equivalent to the maximum permitted shelf life of date. For sampling from 3 heights in 3 rows, one hole was randomly selected and a sample equal to 20 g of date was taken. Three samples were taken from each insectarium. During 25-week storage period of date treated with B. bassiana and Btk, 6 outbreaks occurred in the population of E. kuehniella. The mechanism of the epidemic is in the way that, once the population has increased to a certain threshold, the incidence of the pathogenic epidemic will be mass-dependent, leading to a decreasing trend in the pest population. Therefore, population reduction was estimated to be at 6 to 32 times that of the control. The highest disease mortality rate occurred at the egg and larval developmental stages, so the pathogens caused the highest mortality before the population entered the reproductive stage. Gradually, from the egg growth stage to the complete insect stage, a reduction was observed in the number of individuals which entered the subsequent growth stage. At all stages, the reduction in the treatment population group was faster than the control population. The highest reduction in the number of individuals entering the next developmental stage was associated with the larval developmental stage, followed by developmental stages of the adult, pupal, and egg. Regarding the highest potential of B. bassiana and BtK in reducing the stock pest population, it is very possible to exploit this interaction for biocontrol.

中文翻译：

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球孢白僵菌和苏云金芽孢杆菌的致病性对克氏杆菌种群动态的影响

藏在胡泽斯坦省的最主要的有害生物是疫病菌Ekustia kuehniella Zeller（鳞翅目：Pyralidae）。在这项研究中，研究了苏云金芽孢杆菌Kurstaki细菌和球孢白僵菌致病性真菌对库氏大肠杆菌枣原虫害虫种群动态的影响。为了实现这一目标，将昆虫馆在平均温度27±5°C和相对湿度40±5％的条件下在体外保存6个月，相当于迄今允许的最大保质期。为了从3行中的3个高度进行采样，随机选择了一个孔，并获取了等于20 g日期的样品。从每个昆虫馆采集三个样品。在用B. bassiana和Btk处理的25周的存储期中，库伊氏菌（E. kuehniella）种群发生了6次暴发。流行的机理是，一旦种群增加到一定阈值，病原性流行的发生将是质量依赖性的，从而导致有害生物种群的减少趋势。因此，估计种群减少量是对照组的6到32倍。最高的病死率发生在卵和幼体的发育阶段，因此在种群进入生殖阶段之前，病原体的死亡率最高。从卵的生长阶段到完全的昆虫阶段，逐渐观察到进入随后的生长阶段的个体数量减少。在所有阶段，治疗人群的减少速度都快于对照人群。进入下一个发育阶段的个体数量减少最多的是幼虫发育阶段，其次是成年，p和卵的发育阶段。关于B. bassiana和BtK在减少种群有害生物种群方面的最大潜力，很有可能利用这种相互作用进行生物防治。