Seasonal biology and behaviour of the predatory mirid hyaliodes vitripennis, a beneficial insect of apple orchards in Quebec, Canada

Hyaliodes vitripennis (Say) is a predatory mirid that feeds on spider mites, aphids, and immature stages of various ot her insects. It is sparsely distributed in North America but in the apple orchards of Quebec, Canada, it can be one of the four most important biological control agents of aphids and mites, provided that selective insecticides and other integrated pest man agement practices are used. The objectives of this two year study were to 1) quantify the population distribution of the insect in Quebec orchards, 2) pinpoint appearance dates of its different developmental stages in those orchards, 3) locate preferred mi cro habitats and measure time spent in these various habitats, and 4) compare the suitability of various rearing conditions. The predator was found in 68 85% of visited orchards. First observations were recorded, on average, around the beginning of July, a nd first adults between the end of July and the beginning of August depending on the year. Populations peaked on average 0-1 weeks following the appearance of adults. Only one generation per year was observed. Adults were observed until the first week of September and they spent 95% of their time on the underside of leaves. Among prey tested ( Tetranychus urticae, Panonychus ulmi, Myzus persicae, Macrosiphum euphorbiae and Choristoneura rosaceana ), mirids fed with T. urticae had a higher survival rate and higher longevity. P. ulmi and C. rosaceana larvae were the least suitable preys and aphids were intermediate.