MN Fruit & Vegetable IPM News - Vol. 4, No. 9

Cabbage looper (CL) infestations continue to increase. This week in Rosemount (Dakota Co.) 50% of plants were infested with small CL larvae, and 30% with CL eggs. To our surprise, the apparent increase in imported cabbageworm (ICW) butterflies this year turned out to be checkered white butterflies. This was confirmed by the presence of checkered white larvae, which are quite different in appearance from ICW larvae, on the plants and an adult, which was captured on a sticky card. Please see the August 3, 2001 newsletter article (http://www.vegedge.umn.edu/mnvegnew/vol3/803but.htm) for more information on the checkered white butterfly. Despite the presence of checkered white larvae, CL larvae can cause significantly more defoliation and treatment decisions should be made based only on CL larval infestation levels when CL is the dominant pest.

Yellowing and puckering of snap bean leaves caused by PLH feeding (Eric Burkness, U of MN)

Potato leafhopper (PLH) populations in snap bean continue to exceed threshold this week. In snap beans with >3 trifoliates PLH populations were at 1.1/sweep, and in snap beans with <3 trifoliates PLH populations were 0.5/sweep. In addition to the presence of PLH, we also observed foliar symptoms (puckering and yellowing, see picture) caused by PLH feeding.

European corn borer (ECB) trap catch has remained high in some locations (http://www.vegedge.umn.edu/2007/MNlist.htm). The blacklight trap in St. James (Watonwan Co.) had the high trap catch last week with a one night trap catch of 285 on July 8^th. This may be an indication that the peak of the 2^nd flight of bivoltine ECB may also be high at this location as we have not yet reached the peak of the 2nd flight based on degree days. Most likely the peak of the 2^nd flight (1733 degree days; 50° F base) will occur the week of 7/23 at most locations. Corn earworm (CEW) trap catch in wire mesh pheromone traps across southern MN have remained relatively low. The progress of CEW trap catch can be viewed on the VegEdge website at http://www.vegedge.umn.edu/2007/CEW.htm. In addition to the VegEdge maps for MN, please see the CEW article included in this issue that illustrates how new websites can be used to predict and track the movement of CEW in the Midwest and Northeast U.S. Recent updates, via the national map, do show significant increases in CEW moth flights, including southwest Kansas (>75/night) and Collinsville Illinois (near St. Louis), at >100/night. Thus it appears that the CEW populations just south of the upper Midwest are building and all those checking traps should be watching closely for new flights in the next 10 days.

Return to index

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 July, 2007 by woldx018@umn.edu
The University, including the Minnesota Extension Service, is an equal opportunity educator and employer. Privacy Policy
©1999-2007 Minnesota Extension Service, University of Minnesota. All rights reserved. Contact copyright@extension.umn.edu for information on reproduction or use of this material.