Start surveying and managing weeds in the field where asparagus will be planted before harvesting the current crop. For information on managing identified weeds, review the Integrated Weed Management section for the previous crop. Identify the dominant weed species present, and keep records of them and the severity of their infestations. Also, check weed infestations in adjacent fields. Keep an inventory of the weeds encountered and their relative abundance in the field.
Weeds seen during the early part of the preplant through planting season include many winter annual weeds, established as early as September and October. Summer annuals may start germinating close to planting time.
Perennial weeds can be a major problem in asparagus plantings. Consider selecting alternative fields for asparagus if yellow or purple nutsedge, johnsongrass, bermudagrass, swamp smartweed, or field bindweed are severe.
How to survey
- Walk through each field in a random pattern.
- Rate the degree of infestation for each weed species on your weed survey form . Indicate the growth stage of the weed (seedling or mature). Sketch a map of the field and mark areas with major weed infestations.
- Use either a numeric scale from 1 to 5 (1 being the lightest, 5 being the heaviest), or rate as "light," "medium," or "heavy."
- Check fencerows, ditch banks, field edges, and wet spots as these may be problem areas for weed growth.
- Check areas around the field edges as these areas could be potential sources for wind-disseminated seeds.
- Sketch a map of the field and mark areas with major weed infestations for follow-up control action, noting carefully the location of weeds producing seed.
- Pay particular attention to perennial weeds. Record the dominant species.
Recording weed survey results assists in weed management decisions including herbicide choice and cultivation practices. Information collected over a period of years tells how weed populations are changing and how effective management operations have been.