Fred Fishel
Department of Agronomy
Positive identification of pests, including weeds, is the first step in a sound integrated pest management program. Knowledge of plant morphological features, such as leaf and stem shape, flower type and color, and the presence of hairs make identification relatively easy compared with relying on seed physical characteristics. On occasion, the agricultural producer and other professionals will be challenged to identify a weed by the features of its seed. This can be a daunting task because of the relatively small size of seed, the change in surface characteristics caused by various processes and subtle color variation within even the same species.
The purpose of this publication is to assist those who attempt to identify weeds by their seed characteristics. This guide is intended not only for agricultural professionals, but also those who are hobbyists, such as FFA members. A hand or pocket lens with a magnification power of 10x will be especially helpful in using this guide. For an idea of relative seed size, each photo contains a millimeter ruler. The distance between increments on the sacle is 1 mm. Compare your sample with the color images in IPM1023 to assist in your identification. Seed photographs are grouped by their plant taxonomic family for both broadleaf and grass or grasslike weeds.
Local MU Extension centers can provide information to assist you in pest identification and control decisions. They can help you submit samples to the MU Plant Diagnostic Clinic, http://plantclinic.missouri.edu/, for positive identification.