Julie Faucher Delisle

Université de Montréal
M.Sc. candidate
Supervisor: Jacques Brodeur
Les Shipp
Start: 2011-06-01
End: 2013-04-01

Project

Evaluation of various types of supplemental food for two species of predatory mites, Amblyseius swirskii and Neoseiulus cucumeris (Acari: Phytoseiidae)
This research investigated supplemental food source as a technique to increase the efficiency of two species of predatory mites, Neoseiulus cucumeris and Amblyseius swirskii against the western flower thrips Frankliniella occidentalis. Laboratory assays aimed to assess the suitability of three pollen species – cattail, maize and apple – and eggs of the Mediterranean flour moth as supplemental food source for the predatory mites under study. In terms of rm value, flour moth eggs, cattail pollen and apple pollen were food sources of equal quality for A. swirskii, while apple pollen appeared to stand out for to N. cucumeris. Maize pollen was a less suitable food source for both species. When fed flour moth eggs, A. swirskii and N.cucumeris completed development and showed high rm values. Apple pollen appeared to be an accessible and suitable food source for both predators. Short term (24h period) influence of apple pollen availability on trophic (F. occidentalis larvae as prey) and intraguild (between the predator species) interactions on standardized chrysanthemum was examined. It significantly lowered predation on thrips by N. cucumeris and led to a decrease in intraguild predation for both predators. Following this, the impact of apple pollen on thrips populations and predator’s maintenance on chrysanthemum greenhouse crop was assessed over a 4 weeks period. The introduction of A. swirskii with pollen provided the best control on thrips while N. cucumeris did not remain on the crop when introduced alone. Apple pollen improved thrips control by A. swirskii in chrysanthemum crops through prey numerical response and retention of predators on plants. The lowest rate of heavy dammages were observed when both predators were used together.