In this Issue:


Vegetable Insect Pest Update


Lingering Problems from a Tough Winter

Weekly Trap Counts

Apple Scab Infections

Field Days

Field Day to Examine Orchard Pest and Disease Management

Potato Field Day, Sept. 9th - Becker, Minnesota

Order: 2008 Minnesota Vegetable Guide

Insect, Pest Profiles

Vol 5 No. 10   August 8, 2008

Vegetable Insect Pest Update

Eric Burkness and Bill Hutchison, University of Minnesota

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Cabbage looper larva (E.C. Burkness, U of MN)

This week, in the Rosemount/Apple Valley, MN (Dakota Co.) area, early planted cabbage continues to be harvested.  Diamondback moth (DBM) and imported cabbage worm (ICW) populations are still very low, however, cabbage looper (CL) has finally arrived.  In recent samples 30% of plants were infested with mostly small to medium sized larvae, and about 10% of plants were infested with eggs.  This well exceeds the threshold of 10% of plants infested with one CL larva, and is a treatable infestation.  Remember to continue sampling after insecticide applications are made to verify efficacy and catch any re-infestations at an early stage (see the CL profile).


Striped cucumber beetles (SCB) continue to be found near UMORE Park, but mainly in pumpkin flowers and little foliar feeding damage is present.  As vines close up the rows, you may want to consider treatment options if populations are close to threshold as this will be the last chance to reduce SCB populations.  By now, egg lay has begun and subsequent egg hatch and adult emergence of the 1st generation may create high populations that feed on developing fruit in the fall and there are few options to remedy that situation (see the SCB profile for thresholds and management options).

Potato leafhopper (PLH) numbers in alfalfa in the Rosemount area have remained low at about 0.6 per sweep in 12 inch tall alfalfa.  PLH numbers have remained low in snap beans this season and most snap beans have been harvested now or are close to harvest.

Black light trap catches of European corn borer (ECB) have increased somewhat with the 2nd flight and this week’s peak was at St. James (Watonwan Co.) with a one night catch of 35 moths (see graph).  As of August 5th, we are at 1530 degree days (base 50°F), which indicates that the 1st eggs of the 2nd flight should be hatching this week and the treatment window for 2nd flight ECB is beginning.  Pheromone trap catch for corn earworm (CEW) has picked up significantly this week in Blue Earth (Faribault Co.) and Rosemount (Dakota Co. ) averaging 24 moths per night, and 38 moths per night respectively (see graph).  Most trap data for this past week has indicated increased CEW activity in pheromone traps. 

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Co-Editors: Bill Hutchison (, Department of Entomology, University of Minnesota, Jeanne Ciborowski, Minnesota Department of Agriculture, Ag. Resources Management and Development Division, and Suzanne Wold-Burkness (, 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, , 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: and at the MDA web site in pdf format at:

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Last Revised August, 2008 by
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