In this Issue:
VEGETABLE NEWS
Vegetable Insect Pest Update
STRAWBERRY NEWS
APPLE NEWS
| Vol 4 No. 8 | July 13, 2007 |
Vegetable Insect Pest Update
Eric Burkness & Bill Hutchison, Dept. of Entomology, University of Minnesota, St. Paul
Cabbage looper (CL) levels continue to remain above threshold in cabbage fields at Rosemount. A late seeded field with 4-6 leaves was at 30% plants infested with CL eggs and no larvae present (threshold = 10% plants infested with larvae). These eggs will likely hatch in the next week, and if a second scouting visit shows levels exceeding the 10% larval threshold then treatment will be warranted. We use a larval threshold because of larval susceptibility to rain events and predators and parasitoids. These natural mortality factors can significantly reduce populations and remove the need for additional control measures to be taken. Potato leafhopper (PLH) populations continue to exceed the 1.0 PLH per sweep threshold in flowering snap beans and alfalfa fields have maintained an infestation of 1.0-2.0 PLH per sweep. After a single treatment in cucumber, striped cucumber beetle (SCB) populations have remained very low in Rosemount and plants are now fruiting and are close to harvest.
European corn borer (ECB) trap catches have picked up in most of the state (http://www.vegedge.umn.edu/2007/MNlist.htm). Again, the blacklight trap in St. James (Watonwan Co.) was the high trap location with a one night trap catch of 228 on July 3rd (see graph, below). Populations of ECB have remained above 75 per night since July 3rd at St. James. Through July 10th, degree-days for Rosemount, MN are 1475 (base of 50° F). The higher trap catches statewide may reflect the start of the 2ndflight of bivoltine ECB (1400 degree days at base 50° F) in addition to the continued univoltine ECB flight. With nearly all early planted sweet corn (planted May 15th or earlier) at the silk stage, the combined ECB flights could pose a potential threat for significant egg-lay on sweet corn in this susceptible growth stage. Corn earworm (CEW) trap catches have also increased in wire mesh pheromone traps across southern MN. The highest one night catch of 24 moths was recorded in Blue Earth, MN. The progress of CEW trap catch can be viewed on the VegEdge website.
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.
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Last Revised July, 2007 by woldx018@umn.edu
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