Effects of abiotic factors on the immature development, adult performance, and field parasitism of mass-reared Anastatus parasitoids (Hymenoptera: Eupelmidae)

Abstract

ABSTRACT Anastatus japonicus Ashmead, A. fulloi Sheng, and Wang, and A. dexingensis Sheng and Wang are vital biocontrol agents for the univoltine litchi stink bug Tessaratoma papillosa (Drury) in Taiwan as well as other invasive hemipteran and lepidopteran pests worldwide. An effective augmentative biocontrol programme was established with Anastatus parasitoids produced using eggs of the ailanthus silkmoth (Samia cynthia (Drury)) as factitious hosts. The study’s objective was to evaluate the immature development and adult performance of three Anastatus parasitoid species at 20, 25, and 30°C. The highest numbers of female and total progeny were produced by A. japonicus at 25°C and by A. dexingensis and A. fulloi at 20°C and 30°C, respectively. Anastatus japonicus had higher parasitism rates than A. dexingensis and A. fulloi at all three temperatures. The female ratios increased from 24.9% at 20°C to 70.4% at 30°C. The highest female ratios were recorded during the first two weeks of reproduction, and male progeny’s proportion gradually increased with female age. Anastatus japonicus was selected as the biocontrol agent for mass production based on its high fecundity and female progeny production rates. The field parasitism from the three release sites showed 30–40% of field parasitism during the first nine days of release. A significant reduction of field parasitism occurred after rainfall. The A. japonicus production system developed herein using the eggs of the factitious ailanthus silkmoth host could be commercialised to provide biocontrol against other hemipteran and lepidopteran pests species.