Oviposition preference of Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae) and rates of parasitism by Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) on Lycopersicon esculentum in São José de Ubá, RJ, Brazil

Abstract

Neoleucinodes elegantalis (Guenée) is one of the most important pests in several tomato growing regions of Brazil. The neonate larva enters the fruit shortly after eclosion, a characteristic that limits the effectiveness of insecticides and biological control agents. A better understanding of the cues that elicit or inhibit host-plant location and oviposition by N. elegantalis could lead to novel control strategies. Our findings indicate that N. elegantalis deposited 89% of its eggs on small fruits (23.1±0.95 mm), and that 76% of the eggs were placed on the first four basal fruits within the fruit cluster. The average number of eggs/egg mass was 2.9±0.17 (range 1-13), and approximately 70% of these were deposited in a single oviposition bout. The percentage of plants with one or more egg mass increased from 11.8 to 100% during a 10-wk monitoring period in 1996, and from 8.7 to 80% during a 9-wk period in 1997. At the end of the growing season in 1996, when the number of plants on which N. elegantalis eggs were found was increasing and pesticide applications were declining, the egg parasitoid Trichogramma pretiosum Riley, was observed and collected. During the last three sampling dates of 1996, parasitism rates increased from 2.4 to 28.7%. However, no egg parasitoids were found during the following autumn to winter growing season of 1997.