Damage symptoms, development, and reproductive performance of the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) on fodder maize and cob

In recent years, the biggest threat to maize production has been the invasion of a new exotic pest, the fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae). Therefore, in this study, the damage characteristics, the development, and the reproductive preferences of this pest were evaluated when its larvae were fed on fodder maize and corn cobs. In this context, the weights (g) of larvae, pupae, and adults, pupal period (days), sex ratio (%), longevity (days), oviposition preferences, fecundity (%), egg incubation period (days), and hatchability (%) on fodder maize and corn cobs were assessed. The results exhibited that the FAW larvae were able to feed on and infest both fodder maize and corn cobs, causing significant damage particularly to the cobs making them unsuitable for marketing and human consumption. Moreover, the larvae and pupae from the corn cobs had the greatest weight and were significantly affected by food items. However, the pupal period was shorter in the corn cobs (7.76 days). Regardless of the type of larval feeding, the emergence of females (>62%) was more than that of males. On the contrary, the longevity of adults from larvae fed on fodder maize (7 days) was shorter than that of larvae fed on corn cobs. Feeding larvae on fodder maize or cobs did not significantly influence the reproductive performance of females (pre-oviposition, oviposition, post-oviposition periods, fecundity, and egg hatching rate). However, the larval diet greatly affected the egg hatching which was prolonged when the diet was based on corn cobs. The results of this study could play a significant role in predicting the damage and reproductive performance of FAW in maize fields during their developmental growth, which will further help in developing effective integrated management techniques against this pest.