Weed Identification Available at the Dept. of Agronomy & Plant Genetics

Kevin Cavanaugh, Dept. of Agronomy & Plant Genetics (with author's permission from Minnesota Crop News, May 16, 2002)

Although the spring weather has been cool and wet, many weeds are well on their way to flowering and developing seeds. Some plants that can be observed flowering at this time are Shepherds's Purse, Flixweed, Dandelion, Henbit, Yellow Rocket, and Field Pennycress to name a few.

Many of the weeds flowering between April and May are perennials, winter annuals, and some cases fast growing annuals (e.g. Bedstraw Catchfly).

Weeds can be very competitive in crop production and also can be a source of poisoning to cattle, sheep and horses. Knowing what weeds you have growing in crop production fields and pastures can lead to making the right decision for control. Numerous publications exist than can aid one in making proper identification. Jerry Doll, Weed Scientist at the University of Wisconsin-Madison, made a comparison of several popular weed identification books last year. Of the numerous weed identification books available, he created his top five picks that were most suitable for upper North Central States. You can read Jerry Doll's weed identification review on the Internet at the following web address ( http://ipcm.wisc.edu/wcm/ ). Upon arriving at this web site, click WEEDS, then scroll down and click on "2001 Weed Articles" and search for "Weed ID Reference Comparison," May 24, 2001. I concur with Jerry Doll; no one book is the "perfect weed ID book." Three web pages that offer some useful web links to weed identification and poisonous weeds are listed below.

1. www.uwyo.edu/plants/weeds/links.htm Offers over 100 links to weed science/weed ID web sites
2. www.noble.org/imagegallery/ Offers excellent photos of weeds, shrubs, trees, vines
3. http://sis.agr.gc.ca/pls/pp/poison?p_x=px Poisonous weed link, good photos and poison symptoms.

Weed samples can be sent to the Department of Agronomy and Plant Genetics at the University of Minnesota for identification. There is no charge, but this service is only offered to commercial vegetable producers, and/or those people working in the agricultural crops service sector. See note for HOME OWNERS-WEED ID at the end of the article.

Weed samples that need to be identified can be sent in two ways: (1) by mail or (2) email with attached digital photos. If using Email, enclose background information about the weed along with 2-3 digital photos. Be sure the photos are good quality and in focus so they show the main characteristics of the weed such as the whole plant, stem, leaf structure, and flower. If your are mailing a sample for identification, please follow the guidelines below.

DO NOT place weeds in plastic bags or wrap in plastic. Plants will turn to mush in the mail.
DO NOT tape weeds to paper or manila folders.
Put the plants in a fold of a paper towel or newspaper. Press overnight under the weight of a heavy book and mail them in the paper. If necessary, plants can be gently folded to accommodate the envelope.
Mail all plants samples at the beginning of the week. This will help to avoid having the plant samples sit in the post-office over a weekend.
Send at least two samples of the entire plant that include the top growth of the plant- stems, leaves, and the flowers and/or fruits, if available. Roots are not normally needed for identification of older plants. However, if sending weed seedlings or older plants, please send the entire plant.
Include background information about the plant: perennial, annual, biennial (if known), where found (cropland, near a wetland, edge of field, soil type, sunny/shady location, etc.)
Include your name address, phone number, and/or email.

Mail weed samples to:
Kevin Cavanaugh
Department of Agronomy & Plant Genetics
411 Borlaug Hall
1991 Upper Buford Circle
St. Paul, MN 55108
Digital photos can be sent by e-mail: cavan008@umn.edu

Herbicide recommendations and use:

Information on weed management, herbicide application, and timing can be found in the University of Minnesota Extension Service publication BU-07094-S, "Midwest Vegetable Production Guide for Commercial Growers. This guide is available for $12.00 (+shipping) from the University of Minnesota Extension Service, by calling: (612) 624-4900 or (800) 876-8636; you may also order over the web at: http://www.extension.umn.edu/units/dc/order.html?item=07094

Finally, for those who wish to download limited pages, for specific crops, you may do so from the Purdue Web Site at: http://www.entm.purdue.edu/entomology/ext/targets/ID/index2002.htm You will need Acrobat Reader, to download the PDF files.

HOME OWNERS-WEED ID

Follow the above guidelines when mailing samples to the Yard and Garden Clinic. The Yard and Garden Clinic charges $5.00 for identification. Payment must accompany sample. Check with your University of Minnesota County Extension Office for a Master Gardener who may be able to identify the weed FREE before sending in a sample to Yard and Garden. Yard and Garden University of Minnesota 155 Alderman Hall 1970 Folwell Ave. St. Paul, MN 55108 Also visit the Yard and Garden Web site at: http://www3.extension.umn.edu/projects/yardandgarden/

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

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 directions of the manufacturer

Last Revised May 30, 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.