Differential Parasitism of Several Species of Lepidopteran Eggs by Two Species of Trichogramma 1

Abstract

Populations of insect pests can be controlled by maintaining a continuous population that can support enough parasites to effect a desired level of control (Evans 1930, Knipling and McGuire 1968). For example, Parker et al. (1971) suppressed larval populations of the imported cabbageworm, Pieris rapae (L.), by releasing fertile adults; then the resulting eggs supported an effective population of the egg parasite Trichogramma evanescens (Westwood). Also, Thewke and Puttler (1970) demonstrated that a population of Trichogramma can be maintained by applying lepidopteran eggs artificially in the field. In the present tests, several species of lepidopteran eggs were exposed to Trichogramma in the field to determine whether host characteristics affected rate of parasitism. Our findings may be of value for both monitoring Trichogramma parasitization and determining what host egg may be best used for supporting and increasing a population of Trichogramma in the field.