Weed Control

Weeds are plants whose undesirable qualities outweigh their good points.

Johnsongrass and shattercane are closely related grass weeds that are troublesome and persistent in row crops, where they reduce yield and quality.

This publication will discuss weed management options for Conservation Reserve Enhancement Program (CREP) grassland acres enrolled in Conservation Practices CP1, CP2, and CP10. Areas designated otherwise (e.g., CP22, riparian buffers) are not discussed in this publication.

Alfalfa (Medicago sativa) is an important perennial forage crop used around the world. Alfalfa is the fourth largest crop, in terms of acreage, grown in the United States behind corn, soybeans, and wheat.

Wirestem muhly (Muhlenbergia frondosa) is a perennial grass species that can be problematic in conservation tillage production systems throughout Pennsylvania and the Northeast.

Burcucumber (Sicyos angulatus) is a summer annual broadleaf weed that is becoming a serious problem in agronomic crops.

Herbicides are applied to soil to manage weeds. While it is desirable for the chemicals to control weeds during the season of application, it is not desirable for them to persist and affect subsequent crop growth.

Adjuvants are commonly used in agriculture to improve the performance of pesticides.

Quackgrass (Elytrigia repens) is a widespread, persistent, cool-season, grassy weed found in Pennsylvania row and forage crops. This competitive perennial grass can reduce crop yields up to 95 percent.

The first reported population of triazine resistance in the United States occurred in the late 1960s in Washington State with common groundsel (Senecia vulgaris). Since that first discovery, more than 50 species of weeds scattered throughout the world have developed weed resistance problems.

Weeds are troublesome in many ways. They reduce yield by robbing crops of water, light, space, and soil nutrients. Weeds can replace desirable grass species, filling in gaps or voids and reducing yield and overall quality of pasture and forages.

The weed multiflora rose (Rosa multiflora, Thunb.) is an increasing problem in Pennsylvania pastures and noncropland. It thrives on idle land, fencerows, and minimally maintained, hilly pastures.

Yellow nutsedge (Cyperus esculentus L.) is an aggressive perennial plant that is native to North America and Eurasia. It is a problem weed in field crops throughout the United States.

Eastern black nightshade (Solanum ptycanthum Dun.), an annual broadleaf plant, is an increasing weed problem in northeastern field crop production.

Poly tanks are not designed to last forever. The life of a poly tank will depend, among other things, on the thickness and quality of the material and how much sunlight (UV) it is exposed to. UV protection slows but does not prevent tank aging.

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Glyphosate and Roundup Ready Crops are valuable tools for Wisconsin farmers. The risk of glyphosate-resistant weeds will increase with improper use of glyphosate. Glyphosate-resistant weeds will reduce the value of this technology. New herbicides are not being developed to replace glyphosate. Wisconsin farmers should be proactive leaders and practice glyphosate stewardship.

This video discusses Pokeweed biology and management in field crops.