Morphology and biology of Noorda blitealis (Lepidoptera: Crambidae) immature instar for a biological control perspective.

Moringa oleifera (Capparales: Moringaceae) is a plant grown for its roots, stems and leaves. However, the leaves are attacked by insect pests including larvae of Noorda blitealis (Lepidoptera: Crambidae). These larvae cause a significant reduction in leaf yield and loss of income for growers. This study was conducted to determine some morphological and ecological aspects of larvae, using mass-reared larvae. Parameters such as larva length, body coloration, number of instars and their duration, damages caused on Moringa leaves, and larvae survival rate were collected. Results showed that N. blitealis larvae passed into 5 instars before pupating. The first instar larva averaged 2.4 ± 0.8 mm in length and was light green. At the 5th instar, the larvae reach 10.8 ± 0.4 mm and appear reddish. The mean duration of egg incubation was 3.00 ± 0.35 days, that of larval instars and chrysalis were respectively, 10.61 ± 2.28 days and 9.78 ± 0.42 days. The Kruskal-Wallis test showed that the leaf attack rate depends on the larva's age (p-value < 0.0001). Larvae aged between 4 and 7 days attacked the greatest number of leaflets. Larvae survival rate was 86.67%, for 1st instar and 100% for the other instars. Knowledge of larvae's biological and morphological characters is necessary to identify the pest in the early stages of infestation and develop control methods based on using bioinsecticides could rapidly be developed. [ABSTRACT FROM AUTHOR]