Comparison of the growth and development of beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) on two different diets

Abstract

Beet armyworm (Spodoptera exigua (Hübner)) (Lepidoptera: Noctuidae) is the most economically important sugar beet (Beta vulgaris) pest worldwide. In this study, a comparison was made between two different diets: one was based on Merkx diet (Holidic diet) and the other was based on sugar beet leaf (Oligidic diet). Results showed that the whole development time from larvae to adult between two diets (Merkx and leaf) was not significantly different. For example, developmental time from first instar larvae to adult in Merkx diet was 11.33 days, whilst developmental time of larvae to adult when larvae fed with sugar beet leaf was 10.33 days. However, analysis of variance showed that in some cases like development time of the first instar, third instar and fifth instar larvae and pupae was significantly different between two treatments (p < 0.05). Larval weight showed differences when larvae fed on Merkx diet and sugar beet leaves. For example, significant differences were shown between first, third and fourth instar larvae weight when larvae fed on Merkx diet and sugar beet leaves (p < 0.05). However, significant differences were not observed between weight of second and fifth instar as well as pupae weight when larvae fed on Merkx diet and sugar beet leaves (p > 0.05).