In this issue

Funding Support for Newsletter

Pest Updates, Alerts

European Corn Borer and "UCB" Flights--2002

Revised Vegetable Pesticide "Plant-Back" Updates for 2002

New Farm Bill and the Produce Industry

New Risk Management Publication for Specialty Crop Growers

Pest Updates (A to Z: Infinity and Beyond)

Bill Hutchison, Eric Burkness & Bob Koch, Dept. of Entomology, University of Minnesota

Aster leafhopper -We now understand why ALH infestations have been unusually high for the past 3 weeks in Minnesota. The annual Wisconsin survey, conducted by Dr. Jeff Wyman and Lisa Flak, graduate student, Dept. of Entomology, University of Wisconsin, confirmed high infestations (including late instar nymphs) in northern Missouri in late April. More information about the 2002 survey will soon be posted on the VegEdge site. Infestations in carrot, lettuce and celery (aster flowers for commercial sale) should continue to be monitored and treated as needed. For more information, view the May 24th, 2002 issue; http://www.vegedge.umn.edu/mnvegnew/vol4/524pot.htm

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Bean leaf beetle - BLB infestations have been very high at the Rosemount Agric. Experiment Station in early planted snap beans (May 15th planting date). Lucky for us, Infestations were also high in our seed treatment study with Gaucho (Gustafson) and Cruiser (Syngenta). Untreated check plots (with or without fungicides) approached 90-100% defoliation. BLB overwinters as adults at or near the soil surface, near field borders, nearby woods, etc. The initial flush of adult feeding, by adults that survived overwintering, will hopefully subside in the next 7-10 days. The following generation usually emerges during pod formation (for soybeans and snap beans). If systemic seed treatments have not been used,a single foliar insecticide application will likely be necessary if more than 25% defoliation is present (or, averaging approx. 6-10 "shot-holes" per leaf), on at least 10% of the plants, and seedlings are still in the cotyledon to first trifoliate stage. Complete data and thresholds are not available for snap beans. However, observations in our plots (2001-2002) indicate that if plants are not protected at 25% defoliation, damage is likely to continue.

As more information becomes available on BLB, we will forward this in future issues of the newsletter.

Cutworms - Cutworm activity has been light, overall this year. Exceptions include dingy cutworm outbreaks in NW Minnesota (RR Valley), and some observations in SW Minnesota. Up until this past week, we have not had enough southerly storms to bring black cutworm into the state. For more information on identification and insecticide performance, see last year’s June 8th article at: http://www.vegedge.umn.edu/mnvegnew/vol3/vol3n5.htm

For updates from NW Minnesota (Ian MacRae): http://nwroc.umn.edu/ent/redent.html

For updates from SW Minnesota (Bruce Potter): http://swroc.coafes.umn.edu/SWMNPEST/02News/issue5.htm

Potato leafhopper - PLH adult counts increased substantially this past week (Rosemount), following our first series of significant low pressure (storm) activity, bringing winds from the southern U.S. and considerable rainfall to southern Minnesota. Infestations in alfalfa at Rosemount increase from about 7/100 sweeps on May 28th to 54/100 sweeps on June 10th. In addition to checking newly cut alfalfa for PLH, growers should also watch for early-season increases in snap beans and potatoes.

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Seedcorn maggot - I have not yet heard of any problems with SCM in Minnesota. However, the wet, cool spring weather was very conducive to damage. Sweet corn, snap beans, and cucurbits that did not receive a seed-treatment insecticide, should be watched closely. This is the time of year when larval (maggot) feeding should occur. If you observe uneven emergence, check the surviving seedlings for damage (see photo). If a field is heavily infested, there is not much you can do to save the current stand.

Recent recommendations (June 5th) from Beth Bishop and Walter Pett, Michigan State University: "Bean, corn and vine crop fields are most commonly attacked, although the seedcorn maggot has a fairly wide host range. The adults, small gray flies that look like houseflies, are attracted to soils rich in organic matter for egg laying. Applying manure to soils or plowing down green manure increases the attractiveness of soil for several weeks. Growers should delay planting into such soils.

Once a field has been infested with seedcorn maggots, there is no remedy but to replant. Insecticides cannot salvage fields already infested. If a grower chooses to replant, there are several ways to prevent damage to the second planting. The best solution is to delay replanting until the maggots have matured and the soil has warmed. Mature maggots are about a quarter of an inch long. If a grower finds maggots this size in the field and waits about a week to replant, it should be okay. If maggots are smaller, growers should wait about 1½ to 2 weeks to replant. Planting into soils where maggots are present is risky. Insecticide-treated seed can help as can some soil applications of insecticides where allowed, but the best strategy is to wait. Once the soils warm to around 70° F, there is little danger of damage from seedcorn maggot."

Reprinted with permission: Beth Bishop, Walter Pett, "Seedcorn maggot infestations: What to do?" Michigan State University Vegetable Crop Advisory Team Alert newsletter, 06-05-02.

For more information on seed corn maggot, view the fact sheet at: http://www.vegedge.umn.edu/vegpest/seedmag.htm

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Striped, Spotted Cucumber Beetles - SCBs have been very active this past week at Rosemount, Apple Valley and West of the Twin Cities. They are a little late this year, but occurring in high numbers, averaging 0.5 to 3/plant in some areas. Newly emerging cucurbits (most all varieties) are very susceptible to direct feeding damage, specifically cotyledon to 3rd true leaf stage. Also during this time, some cucurbits, primarily muskmelon and cucumber are susceptible to bacterial wilt, transmitted by the beetles. Unfortunately, we do not presently have many alternatives for control. Check for labeled insecticides for each crop, and the VegEdge Fact Sheet for more information: http://www.vegedge.umn.edu/vegpest/cucs/cukes.htm

Be cool, stay current: For specific pest thresholds and up-to-date insecticide recommendations for each crop, refer to (and order) the "Midwest Vegetable Production Guide for Commercial Growers-2002"; available at: http://www.vegedge.umn.edu/mnvegnew/vol4/524guid.htm

Updates to this guide, including label changes, are also available throughout the year, via PDF format; Purdue University site: http://www.entm.purdue.edu/entomology/ext/targets/ID/index2002.htm

Co-Editors: Bill Hutchison, Department of Entomology, University of Minnesota, hutch002@tc.umn.edu
Jeanne Ciborowski, IPM Program, Minnesota Department of Agriculture, jeanne.ciborowski@state.mn.us
Cindy Tong, Department of Horticulture, University of Minnesota, ctong@extension.umn.edu
Production Editor: Suzanne Wold, Research Assistant, University of Minnesota, woldx018@tc.umn.edu

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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 directions of the manufacturer

Last Revised June 14, 2002.
The University, including the Minnesota Extension Service, is an equal opportunity educator and employer.©2002 Minnesota Extension Service, University of Minnesota. All rights reserved. Contact copyright@extension.umn.edu for information on reproduction or use of this material.