ISHS Acta Horticulturae 422: International Conference on Integrated Fruit Production
OCCURRENCE AND PEST STATUS OF LESSER APPLE WORM GRAPHOLITA PRUNIVORA WALSH IN MICHIGAN APPLE ORCHARDS. |
| Authors: | G. Krawczyk, James W. Johnson |
| Abstract:
Lesser apple worm (LAW) Grapholita prunivora Walsh (Lepidoptera: Tortricidae), a native North American fruit pest is a quarantine insect in Europe and Asia. The presence of LAW in Michigan apple orchards and flight biology were studied during 1991– 1994. Observation in four commercially managed orchards and four abandoned orchards were used for evaluating the lesser apple worm fruit infestation level. Under Michigan weather condition LAW has two generation per season. Study on flight biology showed insect activity only during the crepuscular light, no later than 30 min. after sunset and when air temperature was above 16°C. In commercial managed blocks we found no fruit with injury caused by this insect. In abandoned orchards lesser apple worm caused up to 5% injuries, significantly less than other common fruit feeders as codling moth Cydia pomonella (L.) or oriental fruit moth Grapholita molesta (Busck). | |
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