ISHS Acta Horticulturae 422: International Conference on Integrated Fruit Production
MEASURING AND UNDERSTANDING THE IMPACT OF NATURAL ENEMIES ON APPLE PEST POPULATIONS: LIFE TABLES FOR THE APPLE ERMINE MOTH, YPONOMEUTA MALINELLUS. |
| Author: | U. Kuhlmann |
| Abstract:
A case study is presented of an actual biological control project of the apple ermine moth (AEM), Yponomeuta malinellus Zeller, for Agriculture Canada. The AEM was accidentally introduced into British Columbia in 1981, where it became a significant pest. This paper presents results of estimations of parasitoid and predator impacts on Y. malinellus in Europe. Life table studies were carried out to understand the role of natural enemies in controlling the pest in Europe. The host abundance at the collection site was less than 3 tents per 100 leaf cluster in 1993-1994 and over 4 in 1995. The Y. malinellus population at Biebesheim (Germany) was attacked by 7 different primary parasitoid species. From these parasitoids, the oligophagous larval-pupal and pupal parasitoid Herpestomus brunnicornis and the oligophagous egg-larval parasitoid Ageniaspis fuscicollis Dalman were selected as potential biological control agents for Canada. Insects predators in the present study were abundant, particularly on egg batches. Life tables indicate that the impact of these predators reached 34.9% in 1993 and 37.0% in 1994 of the total generational mortality of Y. malinellus. The impact of the parasitoids in relation to the total generational mortality of Y. malinellus was studied. Results presented indicate that parasitoids killed 6.1% of the AEM in the generation in 1993 and 3.8% in 1994. This is equivalent to 19.0% in 1993 and 13.1% in 1994 of the generational mortality. | |
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