In this Issue:

VEGETABLE NEWS

Vegetable Insect Pest Update

STRAWBERRY NEWS

Berry IPM Update

APPLE NEWS

Adult Apple Maggot Data

Apple Maggot Flight Activity

Weekly Trap Counts

Apple Scab Infections

Order: 2007 Minnesota Vegetable Guide

Insect, Pest Fact Sheets

Berry IPM Update

Thaddeus McCamant, Specialty Crops Management Specialist, Northland Community & Technical College

The 2007 strawberry season is finished everywhere except in a few farms in northern Minnesota. The summer raspberry harvest is in full swing, and a small blueberry harvest is peaking. Fruit quality in summer raspberries is excellent. 

Insect and disease pressure was low this year at most farms. Tarnished plant bug numbers were down.  A few farms that did not spray had little tarnished plant bug damage. There were not enough thunderstorms near harvest to cause major losses from anthracnose. The weather was dry enough near bloom that gray mold was not a problem. There was some bronzing of fruit, but the bronzing appeared to have been caused by heat rather than thrips.

The spittle bug population reached a peak this year. Most people see the foam on different plants without realizing that inside the foam are one or two insects. The insects inside the spittle are in the nymph stage. The adults are called froghoppers and look like a large leafhopper. Like aphids, spittle bug nymphs attach themselves to one section of the stem and rarely move. Aphids tap into the cells that transport sugar from the leaves to the fruit, and their major excrement is honeydew, which is a concentrated form of sugar.

Spittle bug nymphs, by contrast, tap into the xylem cells. Xylem transports water from the roots to the leaves, but within the xylem are small quantities of amino acids that nourish the developing insects. Xylem sap is low in nutrients, so the spittle bugs consume a lot of xylem sap and excrete large quantities of water. Their excrement is the spittle around them.

This year, the spittle bugs hatched shortly before bloom. Some were feeding on the floral buds before moving down the stem. Some deformed berries in strawberry fields could have been caused by spittle bugs, but generally the bugs caused little damage.  The biggest concern with spittle bugs is that the foam bothers pickers. This year in Minnesota, the spittle was not a concern because the nymphs began to mature the week before picking. By the time the berries ripened, all that was left was a little bit of white dust on the stems. They are still in your fields, but they have sprouted wings and are flying around finding new places to lay their eggs. 

There are spray recommendations for spittle bugs but this year there was little reason to spray. The nymphs caused little damage on the fruit and were gone by the time picking started.

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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
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