The Virginia Pest Management Guide (PMG) series lists options for management of major pests: diseases, insects, nematodes, and weeds. These guides are produced by Virginia Cooperative Extension and each guide is revised annually. PMG recommendations are based on research conducted by the Research and Extension Division of Virginia Tech, in cooperation with other land-grant universities, the USDA, and the pest management industry.

The Virginia Pest Management Guide (PMG) series lists options for management of major pests: diseases, insects, nematodes, and weeds. These guides are produced by Virginia Cooperative Extension and each guide is revised annually. PMG recommendations are based on research conducted by the Research and Extension Division of Virginia Tech, in cooperation with other land-grant universities, the USDA, and the pest management industry.

For small fruit growers, weed management is one of the greatest challenges they will face to successfully grow these crops. Factors such as climate, new weed species, weed species shifts, and years of agricultural activity have come together to select for weed species that are aggressive and persistent. Without management, weeds compete with crops for light, nutrients, and water, resulting in reduced vegetative growth of the crop plant, poor fruit quality and lower yield. Stressed crops are also more susceptible to disease and insect infestations, while excessive weed growth itself creates higher humidity in the crop foliage, enhancing disease spread and inviting unwanted insects. Weed management principles for the perennial small fruit crops are similar, with the exception of strawberries in the annual system. Grapes, brambles, blueberries and matted row strawberries are considered permanent plantings in which weed management must be addressed throughout the life of the planting. When compared to annual crops, perennial culture is a greater challenge, as weeds need to be managed through all seasons and perennial weed species increase in numbers and diversity. Understanding seasonal weed thresholds, and integrating cultural and chemical management becomes even more important in the year-round culture.

Herbicides that are usually associated with contamination of straw/hay, turf clippings, manure, and composts are growth regulator herbicides or synthetic auxins, a group of herbicides that mimics plant hormones and regulates growth. These herbicides are labeled for control of broadleaf weeds in grass crops, such as pastures and corn; in turfgrass, including lawns, golf courses, parks, and highway turf; and in noncrop areas. Vegetable and fruit crops, as well as broadleaf ornamentals can inadvertently be injured by these chemicals through drift of spray droplets, volatilization, and spray tank contamination or by residues in straw, manure, turf clippings, or compost. Diagnosing the specific herbicide responsible for the plant damage can be difficult. This publication focuses on damage caused by herbicide residues.