São Paulo State University (Unesp), School of Agricultural and Veterinarian Sciences, Jaboticabal, Brazil.
São Paulo State University (Unesp), School of Agricultural and Veterinarian Sciences, Jaboticabal, Brazil.
J Invertebr Pathol. 2019 Sep;166:107209. doi: 10.1016/j.jip.2019.107209. Epub 2019 Jun 12.
Biological control using entomopathogens and natural enemies is an ecofriendly method for pest management in agriculture. Biological control agents often can be simultaneously employed and compatibility between agents may improve pest suppression. We investigated the influence of the entomopathogen Bacillus thuringiensis (Bt) on the immune system of the sugarcane borer Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) to determine if such changes impact parasitization by Cotesia flavipes Cameron, 1891 (Hymenoptera: Braconidae). The immune response of surviving D. saccharalis larvae fed with an LC dosage of a Bt-based biopesticide (Dipel®) was analyzed (total hemocyte count, hemocyte adhesion, and activities of phenoloxidase and lysozyme). Furthermore, the suitability of surviving Bt-fed larvae as hosts for C. flavipes was assessed by measuring parasitoid attributes such as number and size of teratocytes, weight of pupae, length of adult female tibia and number of emerged adults. Total hemocyte count, but not hemocyte adhesion, total protein content and phenoloxidase activity increased in the hemolymph of non-parasitized Bt-fed larvae (Bt-NP) compared to control larvae (NBt-NP). Lysozyme activity increased only after parasitization without Bt exposure (NBt-P). After parasitization, the immunological parameters activated in Bt-NP larvae decreased to levels at or below those observed in control larvae, showing that C. flavipes can regulate the activated immune response of Bt-fed larvae. The development of C. flavipes was not impaired in Bt-fed larval hosts (Bt-P); no changes were observed for teratocyte size, weight of pupal mass, length of hind tibia and number of adults emerged.
利用昆虫病原生物和天敌进行生物防治是农业害虫管理的一种环保方法。生物防治剂通常可以同时使用，并且剂之间的相容性可能会提高害虫的抑制效果。我们研究了昆虫病原苏云金芽孢杆菌（Bt）对甘蔗螟虫（Diatraea saccharalis）（鳞翅目：夜蛾科）免疫系统的影响，以确定这些变化是否会影响 Cotesia flavipes Cameron（膜翅目：Braconidae）的寄生。分析了用 Bt 为基础的生物农药（Dipel®）的 LC 剂量喂养的幸存 D. saccharalis 幼虫的免疫反应（总血细胞计数、血细胞黏附、酚氧化酶和溶菌酶活性）。此外，通过测量寄生蜂的属性，如畸形细胞的数量和大小、蛹的重量、雌性后足的长度和成虫的数量，评估了幸存的 Bt 喂养幼虫作为 C. flavipes 的宿主的适宜性。与对照幼虫（NBt-NP）相比，未被寄生的 Bt 喂养幼虫（Bt-NP）的血淋巴中的总血细胞计数增加，而血细胞黏附、总蛋白含量和酚氧化酶活性增加。只有在没有 Bt 暴露的情况下进行寄生后，溶菌酶活性才会增加（NBt-P）。寄生后，Bt-NP 幼虫中激活的免疫参数下降到低于或等于对照幼虫的水平，表明 C. flavipes 可以调节 Bt 喂养幼虫激活的免疫反应。C. flavipes 在 Bt 喂养的幼虫宿主中发育不受影响（Bt-P）；畸形细胞大小、蛹重、后足长度和成虫数量均无变化。
