In this Issue:
VEGETABLE NEWS
Summary of Corn Earworm and European Corn Borer Dynamics in 2007
Insecticide Efficacy for Corn Earworm: Small-Plot Trial 2007
BERRY NEWS
APPLE NEWS
2007 Trap Catches for Codling Moth and Dogwood Borer at 5 Apple Orchards Monitored by the MDA
Minnesota Department of Agriculture’s 2007 Exotic Apple Insect Pest Survey
| Vol 4 No. 12 | September 28, 2007 |
Minnesota Department of Agriculture’s 2007 Exotic Apple Insect Pest Survey
Jean Ciborowski, MDA
Four exotic apple insect pests including Apple Ermine Moth (Yponomeuta malinellus), Apple Tortrix (Archips fuscocupreanus), Light Brown Apple Moth (Epiphyas postvittana) (see May 25, 2007 issue for more information on LBAM) and Summer Fruit Tortrix Moth (Adoxophyes orana) were monitored in Minnesota apple orchards this summer. Two traps per insect were set in each of seven MN apple orchards during the last week of April for a total of eight exotic traps per orchard. The traps remained in the orchards until the last week of August. Trap liners were collected every two weeks and checked for these pests by Dr. John Luhman, the MDA’s insect taxonomist.
This was the third year of trapping for the first three insects listed above and the second year of trapping for the Summer Fruit Tortrix moth. Orchards included in the survey were located in metro and southeastern MN counties. We are happy to report that none of the four exotic insect pests were found at any of the seven orchards included in the survey during the past three years.
Here is a brief description of the types of damage caused by each of the four insects:
Apple Ermine Moth (AEM):
If tents and larvae are numerous enough, and serious defoliation occurs, the summer growth of the fruit is stopped and fruits may fall prematurely. However, the severity of AEM damage varies considerably from year to year. Infestations are frequently spaced out by several years and are more common in older orchards. In Washington and Oregon, serious defoliation has been observed in May or June at sites where tents and larvae are numerous.
Apple Tortrix (AT):
In the spring, the caterpillars of the AT feed upon leaves, and less frequently upon blossoms or developing fruits. In addition to feeding, caterpillars injure trees by pruning leaves, flower parts, or fruitlets to construct shelters in which to live. When they are abundant, the caterpillars can defoliate trees.
Light Brown Apple Moth (LBAM):
Light brown apple moth larvae cause damage to foliage and fruit. Early instars feed on tissue beneath the surface layer of leaves. Larger larvae migrate from these positions to construct feeding niches between adjacent leaves, between a leaf and a fruit, in the developing bud or on a single leaf, where the topical leaf roll develops. The late stage larvae feed on all leaf tissue except main veins. Superficial fruit damage is common in apple varieties which form compact fruit clusters. Internal damage to apples is less common, but a young larva may enter the interior of an apple fruit through the calyx. Excreta are usually ejected onto the outside of the fruit which does not happen with the coddling moth.
Summer Fruit Tortrix Moth (SFTM):
In the spring, overwintering larvae feed on emerging leaves and buds. Summer larvae attack the leaves at the tips of the stems and when leaves are in contact with fruit the larvae will graze the upper epidermis and occasionally dig round holes 3 to 6mm deep. The autumn larvae also eat tree leaves and gnaw the fruit. Up to 10-20% fruit loss has occurred in France and Germany.
ACKNOWLEDGEMENTS
Co-Editors: Bill Hutchison (hutch002@umn.edu), Department of Entomology, University of Minnesota, Jeanne Ciborowski, Minnesota Department of Agriculture, Ag. Resources Management and Development Division, and Suzanne Wold-Burkness (woldx018@umn.edu), Department of Entomology, University of Minnesota
The Newsletter is published weekly from May through August, cooperatively, by the Minnesota Department of Agriculture (MDA) and the University of Minnesota (U of MN). Reports are posted on the U of MN and MDA web sites on Fridays. If you have suggestions and/or comments, please send your contributions by 4 p.m., Wednesday to Jeanne Ciborowski, 651-201-6217, jeanne.ciborowski@state.mn.us , MDA, 625 Robert St. North, St. Paul, MN 55155. You can access the Newsletter at the U of MN web site in htm format at: www.vegedge.umn.edu/MNFruit&VegNews/mnindex.htm and at the MDA web site in pdf format at: www.mda.state.mn.us/plants/pestmanagement/ipm/ipmnews.htm
Partial funding for this publication is provided through partnership agreements with the Minnesota Fruit and Vegetable Growers Association (MFVGA) and the United States Department of Agriculture – Risk Management Agency (RMA). These institutions are equal opportunity providers.
DISCLAIMER
Reference to products in this publication is not intended to be an endorsement to the exclusion of others which may have similar uses. Any person using products listed in this publication assumes full responsibility for their use in accordance with current manufacturer directions.
Last Revised September, 2007 by woldx018@umn.edu
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