The effect of entomopathogenic Lecanicillium spp. (Hypocreales: Cordycipitaceae) on the aphid parasitoid Aphidius colemani (Hymenoptera: Aphidiinae)

The effects of entomopathogenic Lecanicillium spp. (Zare and Gams) on Aphidius colemani (Viereck) adult longevity and ovipositional behavior and on the emergence rate and longevity of the F-1 generation of this parasitoid insect were evaluated under laboratory conditions. Moreover, the ability of three strains of Lecanicillium spp. to penetrate the cuticle of aphids parasitized by A. colemani at different larval stages was investigated. Although fungal treatments at high concentrations (10(7) conidia/ml) reduced adult longevity, no significant effects were observed at lower concentrations. The number of ovipositional probings, sting failure rate of the ovipositor, and time intervals between periods of ovipositional behavior were not significantly different between the experimental groups and controls at all concentrations for all fungal strains. Fungal inoculation showed no significant effects on the emergence rate and longevity of the adult A. colemani F-1 generation. Fungal penetration was detected in 60 % of aphids inoculated with fungi 7 days after parasitoid exposure. However, fungal detection was drastically reduced and undetectable when fungal inoculation occurred 8 and 9 days after parasitization, respectively. Our results suggest the coapplication of Lecanicillium spp. and A. colemani for aphid control is possible under certain conditions because of their high compatibility.