Comparative assessment of five native Anastatus parasitoids for optimized biological control of Halyomorpha halys

The brown marmorated stink bug (BMSB), Halyomorpha halys, is a polyphagous invasive pest with a host range exceeding 300 plant species worldwide, causing significant economic losses. To identify the most effective biological control agents for BMSB, we comparatively assessed the parasitism performance of five Asian Anastatus parasitoids, i.e., A. fulloi, A. gansuensis, A. japonicus, A. meilingensis and A. shichengensis. All five parasitoids successfully parasitized and emerged from BMSB eggs of varying ages (0-, 2-, and 4-day old), with emergence rates ranging from 65.63% to 100%. Among the tested species, A. japonicus demonstrated the highest total number of parasitized and host-fed eggs, followed by A. meilingensis and A. shichengensis. Developmental times varied, with A. gansuensis exhibiting the longest duration and A. shichengensis the shortest. Progeny sex ratios were predominantly male-biased (> 80%) for most parasitoids, except A. gansuensis, which produced exclusively female progeny, and A. shichengensis, which produced over 80% female off spring on 0-day old eggs. In choice tests, only A. shichengensis showed significantly higher host-feeding on 4-day old eggs compared to 2-day old eggs. Anastatus gansuensis had the lowest number of parasitized and killed eggs among the five parasitoid wasps across the three BMSB egg age groups. Our findings suggest that A. gansuensis and A. shichengensis are better suited for inoculative control programs due to their high female progeny rates, while A. japonicus, A. meilingensis and A. shichengensis could be more appropriate for inundative releases because of their high host killing rates. However, none of the performance parameters of A. fulloi showed significant advantages. Overall, A. shichengensis demonstrated superior efficacy in both inundative release and sustainable control strategies. These insights contribute to optimizing rear ing methods and field-release strategies, paving the way for sustainable pest management practices and reducing reliance on chemical pesticides.