Weed Control

NOTE:  For the herbicides listed below, one product trade name and formulation is provided for each active ingredient (common name) as an example of rates, days to harvest (dh), REI, and special instructions. In many cases there are other products available with the same active ingredient. Please see Table 17 and Alphabetical Listing by Trade Name for more information on products with the same active ingredients.

New Plantings

fluazifop (Fusilade DX): 16 to 24 oz/A (REI 12h, Group 1). (1 year to harvest) Nonbearing asparagus ONLY. For grass weed control only. Apply to actively growing grasses (see product label for susceptible stage). Add 1 gal crop oil concentrate or 1 qt nonionic surfactant per 100 gal of spray.

glyphosate (Roundup 4S): 1 to 5 qt/A (REI 12h, Group 9). Preplant or stale seedbed application. See Stale Seedbed Technique.

paraquat (Gramoxone Inteon* 2S): 1.5 to 2.7 pts/A (REI 12h, Group 22). Preplant or stale seedbed application. See Stale Seedbed Technique.

pelargonic acid (Scythe 4.2): 3 to 10 gal/A (REI 24h, Group 27). See Stale Seedbed Technique.

Annual Weeds in Established Beds

diuron (Karmex 80WP): 2 to 4 lb/A (REI 12h, Group 7). Use the higher rate of diuron on clay soils or on very weedy fields, in the spring, after discing, preemergence to both crop and weeds. Repeat, if necessary, after cutting season. The soil must be kept moist to activate diuron. If weeds start to germinate, cultivate lightly (not deeper than 1”) and irrigate during cutting season. Do not use on newly seeded asparagus or on young plants or crowns during the first season. Do not use diuron on a bed the year it is to be abandoned and planted to another kind of vegetable.

norflurazon (Solicam 80DF): 2.5 to 5 lb/A (REI 12h, Group 12). Apply after the cutting season. Controls most grasses and several broadleaf weeds. Also will suppress yellow nutsedge. Cannot be used unless planting is at least 12 months old.

halosulfuron (Sandea 75 WSG): 1/2 to 1 oz/A (1 dh, REI 12h, Group 2). For transplanted crowns and established beds only. For transplanted crowns, apply no sooner than 6 weeks after fern emergence. For established beds, apply during or at the end of the harvest season after asparagus has been clean cut. May also be applied as a directed spray to the base of the ferns. Contact with ferns will cause yellowing. Will provide preemergence and postemergence control of many weeds. Do not apply more than 2 times per season and do not exceed 2 oz/A per year. See label for list of weeds and other precautions.

mesotrione (Callisto 4SC):  0.094 -0.24 lb/A.  (REI 12 hr, Group 28)  Apply 3 to 7.7 fluid ounces per acre Callisto 4SC prior to spear emergence in the spring, after final harvest, or both, to control many winter and summer annual broadleaf weeds.  Till the field or tank-mix with Gramoxone inteon to eliminate emerged spears when Callisto is applied after harvest or crop injury may be observed as white or white streaks in the stems and fern when treated spears grow.  Callisto provides excellent control of horseweed (also called marestail or stickweed), including glyphosate tolerant strains, and common lambsquarter.  Use the lower rate on coarse-textured (sandy) soils low in organic matter, and the higher rate on fine-textured (silt and clay) soils.  Callisto does not control annual grasses.  Tank-mix Callisto with a residual annual grass herbicide to control annual grasses.  Add oil concentrate to be 1 percent of the spray solution (1 gallon per 100 gallons of spray solution) or a nonionic surfactant to be 0.25 percent of the spray solution (1 quart per 100 gallons of spray solution) if target weeds are emerged at the time of application.  Do NOT apply more  than 7.7 fluid ounces of Callisto per acre per year, and do NOT make more than two Callisto application per year.

metribuzin (Sencor 75DF): 1 1/3 to 2 2/3 lb/A (14 dh, REI 12h, Group 5). Apply in 40 gal water/A as a preemergence broadcast spray in the spring before spears emerge. If field is to be disced, apply after discing but before crop emergence. Do not use on newly seeded asparagus or on young plants or crowns during first season. Do not apply to established beds after emergence. Fair on grasses.

trifluralin (Treflan HFP): 1 to 4 pt/A (REI 12h, Group 3). Established plantings only. Incorporate either before spear emergence in the spring or after the last harvest. Can be used both spring and after harvest by splitting the rate in half for each application. Do not apply after spring spears have begun to emerge.

napropamide (Devrinol 50DF): 4 to 8 lb/A (REI 12h, Group 15). Use lower rate on light soil and higher rate on heavy soil. Incorporate thoroughly prior to spear emergence to a depth of 1”.

terbacil (Sinbar 80 WP): 1 1/2 lb/A (5 dh REI 12h, Group 5). Apply prior to spear emergence, after a clean cutting, or after the last harvest. If more than one application is made, total rate cannot exceed 2 1/2 lb/A per year. Do not apply if roots are exposed or if the planting is weak; see label.

paraquat (Gramoxone Inteon* 2S): 2 to 4pts/A (REI 12h, Group 22). Apply prior to emergence of crop or after last clean cut harvest. Asparagus plants that have emerged at time of application will be killed.

pelargonic acid (Scythe 4.2): 3% to 10% (REI 24h, Group 27). Use a 3-5% solution for annual weeds (4-6 oz/gal water, a 5-7% solution for biennial and perennial weeds (6-9 oz/gal water), and 7-10% solution for maximum burndown (9-13 oz/gal water). Delivery rate for boom applications should be 75 to 200 gallons of spray solution per acre; complete coverage of weed foliage is essential. Use a DIRECTED/ SHIELDED SPRAY; contact with crop will cause injury. For hand-held equipment, spray to completely wet all weed foliage but not to the point of runoff. Repeat applications as necessary. Tank mixes are allowed with this product. These include tank mixes with glyphosate (Roundup), sulfosate (Touchdown), and residual herbicides. See label for complete details.

Bindweed, Dandelion, Plantain, and Creeping Yellow Cress

2,4-D sodium salt (Amine 4): 2 to 3 lb/A (REI 48h, Group 4) of active ingredient. Spot spray when weeds appear. Keep spray off spears and fern. 2,4-D is hazardous to most horticultural crops. Drift or sprays may seriously injure or reduce yields of these crops. May help to control unwanted seedling asparagus.

Quackgrass and Other Perennials in Established Beds

glyphosate (Roundup 4S): 2 to 3 qt/A (REI 12h, Group 9). Apply to emerged weeds well before spear emergence in the spring as contact with spears will result in serious crop injury.

Perennial Weeds in Established Beds

glyphosate (Roundup 4S): 2 to 3 qt/A (REI 12h, Group 9). Apply after cutting season, after removal of all growing spears and fern (clean cut). Contact with growing spears or fern will result in crop injury. For later application use directed or shielded sprays to prevent plant contact.