Submitted to: Pacific Northwest Vegetable Association Proceedings
Publication Type: Proceedings
Publication Acceptance Date: September 1, 1994
Publication Date: N/A
Interpretive Summary: Weed control in asparagus presents unique challenges to growers. Since asparagus is cut from early spring to late June there is no crop canopy early in the season to suppress weeds. Cultivation destroys small weed seedlings, but if not properly timed, can injure the asparagus and will delay harvest 7 to 10 days. Numerous selective herbicides are available for weed control in asparagus, but must be carefully selected and used correctly to avoid crop injury and to control the weeds present. Options for weed control practices in asparagus are presented and discussed, including mechanical, cultural, and chemical control options.
Technical Abstract: Herbicides and repeated cultivations are used to control weeds during asparagus establishment. Selecting a site free of perennial weeds and using glyphosate or paraquat as a sterile seedbed technique helps control many weeds. Linuron or terbacil can be applied to direct seeded asparagus if a band of activated charcoal is applied over the seed row. After asparagus has emerged, linuron can be applied for broadleaf weed control and fluazifop-P or sethoxydim for grass weeds. Repeated cultivations and handweeding may supplement herbicides. Weed control in established asparagus includes cultivation, preemergence herbicides, and spot treating or hand weeding weed escapes. Spring cultivation incorporates the fern and removes winter annual weeds. Preemergence herbicides labeled for use in asparagus are napropamide, trifluralin, linuron, metribuzin, diuron, simazine, norflurazon, and terbacil. During the cutting season hoe out perennial or herbicide resistant weed patches or spot treat with glyphosate. Escape broadleaf weeds can be controlled with 2,4-D, dicamba, and linuron and grass weeds can be controlled with fluazifop-P. Cultivation controls weeds but delays harvest and may injure shallow asparagus crowns. During the fern stage of growth 2,4-D and glyphosate may be applied as a shielded and directed spray at the base of the fern.