Natural Biological Control and Key Mortality Factors of the Pickleworm, Diaphania nitidalis Stoll (Lepidoptera: Pyralidae), in Cucumber

Abstract

ABSTRACT A field study was conducted to determine the natural biological control and key mortality factors of the pickleworm, Diaphania nitidalis Stoll (Lepidoptera: Pyralidae), in two cucumber varieties. Field data for mortality factors were used to construct an ecological life table for this pest. Predation by Paratrechina sp. (Hymenoptera: Formicidae) and parasitism by Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) were the most important mortality factors for the egg stage of D. nitidalis, whereas the most important factor for the pupal stage was predation by Labidus coecus Latr. (Hymenoptera: Formicidae). Larval phase was the critical mortality stage, and third and fifth instars were the critical mortality ones. Key mortality factors of D. nitidalis were predation of its larva by Polybia ignobillis Haliday (Hymenoptera: Vespidae) in the third instar and impact of rainfall during fifth instar.