Mass rearing of <i>Chelonus</i> parasitoids with the alternative host <i>Corcyra cephalonica</i> : a promising biocontrol option against fall armyworm <i>Spodoptera frugiperda</i>
Zhen Shen, Yong‐Ming Chen, Mi Huang, Haneef Tariq, Liang‐De Tang, Jian Wei, Qiong Bai, Kelvin Kamfwa, Ricardo Ramírez‐Romero, Lucie S. Monticelli, Lian‐Sheng Zang
Abstract
BACKGROUND: Fall armyworm (FAW), Spodoptera frugiperda, is an invasive and highly destructive pest of staple and cash crops worldwide. Parasitoids of the genus Chelonus are important natural enemies of FAW in both its native and invasive ranges. In this study, we first compared biological and morphological parameters of Chelonus bifoveolatus reared on Corcyra cephalonica eggs of various ages. Next, we used life table analysis method to assess the reproductive capacity and population growth of C. bifoveolatus on C. cephalonica and its biocontrol potential against FAW. RESULTS: Our work showed that C. bifoveolatus successfully developed on C. cephalonica eggs of varying ages, with parasitism rates and development time declining with host age. The C. bifoveolatus reared on FAW exhibited higher net reproductive rate, intrinsic rate of increase, and finite rate of increase, but shorter adult longevity, life expectancy, age-specific survival rate, and reproductive value compared to those reared on C. cephalonica. By day 80, the population of C. bifoveolatus which was reared on the factitious host C. cephalonica, was projected to produce 178 females, 402 males, and 88 651 preadult offspring. However, although the overall production on C. cephalonica was lower compared to the primary pest host S. frugiperda, the resulting C. bifoveolatus population retained adequate pest-killing ability. When parasitizing FAW, C. bifoveolatus parasitized a total of 1543 eggs over its lifespan. CONCLUSION: Our work demonstrated that the rice moth, is a suitable factitious host for the (commercial) mass-rearing of C. bifoveolatus. To support higher parasitism rates and a greater proportion of females, younger (0-1-day old age) C. cephalonica eggs were recommended for mass-rearing C. bifoveolatus. This use of C. cephalonica eggs, compared to rearing C. bifoveolatus on S. frugiperda, was more cost-effective and required less time and labor. These findings provide valuable insights for improving C. bifoveolatus mass-rearing protocols. © 2025 Society of Chemical Industry.