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

Abstract

The biggest threat to maize production in recent years is the invasion of a new exotic pest fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae). Therefore, this study aimed to evaluate the damage characteristics, development, and reproductive preferences of this pest when its larvae fed on fodder maize and cobs. In this context, 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 and cobs were assessed. Results exhibited that FAW larvae were able to feed and infest both fodder and cobs, causing significant damage particularly on cobs by making them unsuitable for marketing and human consumption. Moreover, larvae and pupae from cobs had the greatest weight and were significantly affected by food items. However, the pupal period was shorter in cobs (7.76 days). Regardless of the type of larval feeding, emergency of females (>62%) was more than that of males. On the contrary, the longevity of adults from larvae fed on fodder (7 days) was shorter than that of cobs. Feeding larvae on fodder or cob didn't influence significantly 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 long in cob. 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 against this pest.

Can Telenomus remus and Trichogramma foersteri be used in combination against the fall armyworm, Spodoptera frugiperda?

“…remus and T. foersteri on S. frugiperda eggs was reduced in egg masses with two layers compared to those with one layer. Similar findings have been observed in other parasitoid species Mohamed et al, 2023). For example, the number of eggs parasitized by T. atopovirilia Oatman & Platner and T. pretiosum Riley was higher in single-layer egg masses than in those with two layers.…”

“…For example, the number of eggs parasitized by T. atopovirilia Oatman & Platner and T. pretiosum Riley was higher in single-layer egg masses than in those with two layers. Likewise, a decrease in the parasitism of Trichogrammatoidea bactrae Nagaraja was observed when the parasitoid had access to egg masses containing more than 250 eggs arranged in two or three layers (Mohamed et al, 2023). Generally, variations in parasitism in egg masses with multiple layers are attributed to the inability of certain parasitoids to parasitize the eggs in the lower layers, except for those located at the edge of the egg masses, which can be easily reached from the side (Carneiro & Fernandes, 2012).…”

Basic Developmental Characteristics of the Fall Armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), Reared under Laboratory Conditions

“…In this study, it was observed that the fecundity of the FAW was relatively high and comparable to that of previous studies conducted under similar conditions [27,[34][35][36]. Moreover, just like the established life cycle of the FAW, each larva in this experiment went through six instar stages.…”