Universidade Federal da Grande Dourados - UFGD, Departamento de Ciências Agrárias, Dourados, MS, Brasil.
Universidade Federal da Grande Dourados - UFGD, Departamento de Ciências Biológicas e Ambientais, Dourados, MS, Brasil.
Braz J Biol. 2022 Oct 7;82:e263443. doi: 10.1590/1519-6984.263443. eCollection 2022.
Parasitoids control insect pests, but their number per host affects their efficiency. The objective of this work was to evaluate the best density of Tetrastichus howardi (Olliff, 1893) (Hymenoptera: Eulophidae) individuals parasitizing fourth instar Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae) larvae in greenhouse conditions. These larvae were exposed to parasitism by T. howardi females with 1:1, 3:1, 6:1, 9:1, 12:1, 15:1 and 18:1 parasitoid/host ratios with 10 replications during 96 hours. After this period the larvae were kept on host plants (Brassica oleracea) until pupa formation. Tetrastichus howardi parasitized and reproduced in P. xylostella larvae at all its densities tested, but with higher values, 84% and 10 ± 2.4 individuals, respectively, with 9:1 parasitoids/host. Nine T. howardi females per P. xylostella larvae are the adequate number to manage this insect pest.
寄生蜂控制着昆虫的数量，但每个宿主身上寄生蜂的数量会影响它们的效率。本研究的目的是评估在温室条件下，每头小菜蛾幼虫（Plutella xylostella (Linnaeus, 1758)）（鳞翅目：菜蛾科）被 1 比 1、3 比 1、6 比 1、9 比 1、12 比 1、15 比 1 和 18 比 1 的阔柄跳小蜂（Tetrastichus howardi (Olliff, 1893)）（膜翅目：跳小蜂科）雌蜂寄生的最佳密度。这些幼虫在 96 小时内暴露于 T. howardi 雌蜂的寄生下，寄生率分别为 1:1、3:1、6:1、9:1、12:1、15:1 和 18:1，每个处理重复 10 次。在这段时间之后，幼虫被保存在寄主植物（甘蓝）上，直到化蛹。T. howardi 在所有测试的密度下都能寄生和繁殖小菜蛾幼虫，但在 9:1 的寄生率下，寄生率和繁殖量分别达到了 84%和 10±2.4 头。每头小菜蛾幼虫有 9 头阔柄跳小蜂是管理这种害虫的适宜数量。
