Unveiling the parasitoid Euplectrus carinifer for controlling Chrysodeixis chalcites larvae in greenhouse environments

The golden twin-spot moth or tomato looper, Chrysodeixis chalcites (Lepidoptera: Noctuidae), is a global pest, causing extensive damage to various crops and ornamental plants, leading to substantial economic losses. In 2018, an unidentified parasitic wasp was found in several greenhouses, where minimal damage from C. chalcites larvae was reported. This prompted an investigation to identify and characterize the species and analyze its life- history parameters. Using an integrative morpho-bio-molecular approach, the parasitic wasp was identified as Euplectrus carinifer (Hymenoptera: Eulophidae). The study revealed that E. carinifer is a gregarious ectoparasitoid capable of parasitizing third to fifth (L3-L5) larval instars of C. chalcites, meanwhile no parasitism was observed on the first and second (L1-L2) larval instars. In a no-choice test, parasitism rates of E. carinifer were 45 % for L3, 75 % for L4 and 40 % for L5. Developmental time from egg to adult E. carinifer was 19.1 ± 0.2 days for L3, 20.0 ± 0.1 days for L4, and 21.5 ± 0.2 days for L5, at 22 ◦C. The average number of wasps emerging as adults was 3.7 ± 0.4 on L3, 7.7 ± 0.9 on L4, and 17.5 ± 1.6 on L5. In a choice test (L1-L5), female wasps showed a preference for L5 larvae (53.3 %), followed by L4 (26.7 %), and L3 (20.0 %). Currently, no effective commercially available biological control agents exists in The Netherlands for man- aging C. chalcites. These findings suggest that E. carinifer holds substantial promise as a biological control agent for C. chalcites larvae in greenhouse environments. 1.