Effects of larval diet on the development and reproduction of Argyrotaenia sphaleropa (Meyrick) (Lepidoptera: Tortricidae)

Abstract

The effect of six natural diets on the development and reproduction of Argyrotaenia sphaleropa (Meyrick) was measured under laboratory conditions, at 23 ±1ºC temperature, 70 ± 10% RH, and photoperiod of 16L:8D. Larvae were reared on three types of diet (spring leaves, summer leaves and fruits) from two different host plants (apple tree and grapevine). Larval development, number of instars, survival, weight of pupae, fecundity, and fertility varied as a function of diets. The shortest time span of larval development, the greatest pupal weight, and the greatest adult fecundity and fertility was observed on insects feeding on spring apple leaves. The duration of larval development was longer on fruits than on leaves. The lowest larval survival occurred on apple fruits. Larvae with a higher number of instars generally had an increase in the time span of larval development. Larval development time span (4 out of 6 treatments) as well as pupal development time span (5 out of 6 treatments) was sex dependant. On all diets the females deposited the highest number of eggs on the first day of oviposition. The results obtained reinforce the hypothesis that the larvae of A. sphaleropa first feed on both apple and grapevine leaves, and then move to the fruits, where they cause serious damage.