Infestation of European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), a key pest of peppers (Capsicum annuum L.), was studied to explore the cause of infestation differences in pungent versus sweet types of peppers. Our objectives were to determine whether O. nubilalis adults show an ovipositional preference or larval development effects among pepper types that vary in levels of capsaicin and dihydrocapsaicin, which is measured in Scoville heat units (SHU). Five pepper types with a range in hotness were tested: bell (0 SHU), sweet banana (0 SHU), hot wax (1125 SHU), jalapeño (5,000 SHU), and cayenne (40,000 SHU). Oviposition was studied after artificial infestation in laboratory cages, small and large field cages, and after natural infestation in choice and no-choice field trials. No ovipositional preference was detected for cage no-choice or choice assays. Field choice oviposition trials with 5 pepper types had no differences in either egg mass density or larval infestation. A no-choice field trial with 3 pepper types found there was no difference in oviposition, but larval infestation varied significantly, with bell peppers having the highest infestation and jalapeños the least. It is concluded that O. nubilalis females show no ovipositional preference among the pepper types tested. Larval development time was significantly longer on jalapeños and significantly longer on pungent than on sweet peppers. Larval survival was not significantly different among types. These results suggest that the difference in infestation must be due to behavioral or physical factors after egg laying and before larvae enter the fruit.
European corn borer