Weeds, Poisonous Plants, & Other Pests

Weeds Management & Control

PNW Weed Management Handbook - This handbook is designed as a quick and ready reference for weed control practices used in various cropping systems or sites/situations in Oregon, Washington, and Idaho. Because chemical regulation of plant growth is complex and requires considerable knowledge, a large portion of the handbook is devoted to registered uses of herbicides, crop desiccants, and some plant growth regulators. Scroll to the 'Weed Control in Pasture and Rangeland' chapter for commonly used herbicides. Always read the chemical label prior to any application!

Managing Summer Weeds in Pastures - The first step in developing a plan for weed management is to identify the problem plants properly. Once identified, the second step is to take the time to learn about the plant’s life cycle and biology. For example, find out if the weed is an annual, biennial, or perennial plant.

Perennial Weed Biology Management - Perennial plants live at least 2 years; some live for decades. Most perennial weeds reproduce both by seeds and by the spread of energy-storing vegetative parts, such as roots or tubers. This combination of reproductive mechanisms makes the management of perennial weeds difficult. By understanding how perennial weeds reproduce and spread, land managers are better able to plan a successful weed management strategy.

Perennial Weed Control - For intelligent and efficient weed control, some knowledge of the life cycles of weeds is useful. The life cycle of a weed is simply its seasonal pattern of growth and reproduction. For example, an annual life cycle means that a weed goes from seed to seed in one growing season or one year.

Foxtail Control in Pastures and Hayground - Foxtail is a problematic grass in pastures and hay ground and infestations need immediate attention. This fact sheet covers reasonable treatment regimes to tackle the infestation.

Poisonous Plants: 

Poisonous Plants to Livestock - Table of poisonous plants and the species it affects, including the scientific name, common name, poisonous parts of the plant, and the primary poisons.

Plants Poisonous to Livestock in the Western States - This bulletin describes more than 330 of the principal poisonous plants growing on western ranges and signs of poisoning in livestock. Suggestions are included for the prevention of livestock poisoning by plants.

Poisonous Plants Commonly Found in Oregon Pastures - In-depth information about poisonous plants found in pasture areas.  Includes detailed toxicity definitions and colored photos of common weeds.

Other pests that affect pastures:

Invertebrate Pest Management for Pacific Northwest Pastures - This publication identifies common invertebrate pests and provides the ecological and control descriptions needed to develop successful pest-management programs.

Pasture and Grass Hay Pests -  The Pacific Northwest Pest Management Handbook lists common pasture and grass hay pests and offers a list of pesticides labeled for each.  

Armyworms in Grass Pastures and Corn in Western Oregon -  Armyworms are a serious pest of turf, forage, and seed grasses; small grains, and corn throughout North America. This publication discusses identification, life cycle, monitoring, action thresholds, biological control, organic controls, and chemical controls of armyworms. Includes color photos for identification.

Meadow Voles and Pocket Gophers: Management in Lawns, Gardens, and Croplands - Meadow voles and pocket gophers cause significant damage to rangeland, alfalfa, pastures, and other agricultural crops. Combined or alone, forage losses from gophers and/or voles have been estimated at 10 to 50 percent in pastures and alfalfa. This publication presents methods of management and the difference between the two rodents.

Controlling Pocket Gopher Damage to Agricultural Crops -  Pocket gophers cause considerable damage to hay and grain crops as well as to cherry, apple, pear, and filbert orchards. Some of the losses are a direct result of the feeding activities of gophers: eating alfalfa hay and filbert nuts. Other losses result from tunneling and mound-building activities: soil and rocks from mounds damage harvesting machinery and degrade the quality of crops. This publication describes activities designed to reduce damages by pocket gophers to hay, grain, and orchard crops.

Endophyte Toxins in Grass and other Feed Sources - Grazing animals on grass seed fields and feeding grass seed straw can be advantageous to both livestock producers and grass seed growers. Problems may develop, however, if livestock consume varieties of tall fescue and perennial ryegrass that are intended for use as turf. Some turf varieties are infected with an endophyte, which produces toxins harmful to livestock.

Moss in Pastures - Soil fertility is often one of the key factors of moss infestations in pastures. In many cases, providing appropriate nutrients will allow grasses and legumes to crowd out the moss.  Read this article to learn more.