Abstracts
Résumé
La livrée des forêts (Malacosoma disstria Hübner) est une espèce indigène largement répandue au Canada et aux États-Unis. Elle est considérée comme le plus important insecte défoliateur des forêts de feuillus du Canada. Les épidémies peuvent couvrir de vastes territoires. Cette espèce cause aussi des infestations importantes dans les érablières. Considérant les sommes investies pour mettre en place les installations acéricoles, des pertes de rendement liées à la défoliation par un insecte forestier sont difficilement envisageables. En 2024, des inventaires automnaux de la livrée des forêts au Témiscouata ont permis de délimiter plusieurs secteurs dans lesquels les populations hivernales étaient suffisamment élevées pour anticiper des défoliations importantes au printemps suivant. Après avoir obtenu l’engagement financier des propriétaires, la SOPFIM (Société de protection des forêts contre les insectes et maladies) a, pour la première fois de son histoire, mis en place un programme de lutte pour combattre un insecte dans des forêts de feuillus, soit des érablières en production acéricole. Ce programme de protection aérienne implique l’épandage d’un insecticide biologique (Bacillus thuringiensis var. kurstaki) couvrant un total de 3 606 ha d’érablières en production acéricole. Les résultats montrent que les secteurs protégés ont peu été affectés par la livrée des forêts, le niveau de défoliation variant de 2 à 13 % pour les érablières protégées, et plus de 75 % de ces peuplements avaient subi moins de 10 % de défoliation. L’article présente les grandes lignes, les défis et les résultats de cette opération de protection unique dans l’histoire du Québec.
Mots-clés :
- défoliation,
- épandage aérien,
- érablière acéricole,
- insecticide biologique,
- livrée des forêts
Abstract
The forest tent caterpillar moth (Malacosoma disstria Hübner) is a native species widely distributed throughout Canada and the United States. Its larvae are considered the most important defoliator of hardwood forests in Canada, and outbreaks can cover extensive areas. This species can cause significant infestations in maple forests, and considering the investment required to establish maple syrup production facilities, yield losses due to insect defoliation are a serious challenge. In fall 2024, inventories of overwintering forest tent caterpillar moth egg masses in the Témiscouata region (Québec, Canada) identified several areas where populations were high enough for significant defoliation to be expected the following spring. After obtaining a financial commitment from local landowners, SOPFIM (Société de protection des forêts contre les insectes et maladies) initiated its first insect control program in a hardwood forest context, namely in maple stands managed for maple syrup production. This aerial protection program involved the application of a biological insecticide (Bacillus thuringiensis var. kurstaki) over 3,606 ha of maple forest. Results show that treated stands were little affected by larvae of the forest tent caterpillar moth. Defoliation rates ranged from 2% to 13% in protected maple stands, and more than 75% of these stands showed less than 10% defoliation. This article outlines the main points, challenges and results of this operation, the first of its kind in Québec.
Keywords:
- aerial spraying,
- biological insecticide,
- defoliation,
- forest tent caterpillar moth,
- sugar bush
Appendices
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