Weed Control

NOTES: For the herbicides listed below, one product trade name and formulation is provided for each active ingredient along with preharvest interval (PHI), restricted entry interval (REI), resistance management group number, and example of rates and special instructions. In many cases, there are other products available with the same active ingredient. However, not all products with the same active ingredient are registered for use in a crop. Always check the product label to be sure that the crop is listed before using. 

Stale Seedbed

See Stale Seedbed Technique for information on the use of these herbicides or flaming.

  • carfentrazone (Aim EC): REI 12h, Group 14.
  • glyphosate (Roundup Power Max): PHI 7d, REI 4h, Group 9.
  • pelargonic acid (Scythe): PHI 1d, REI 12h, Group 0.

Preemergent Herbicides (before weeds germinate)

cycloate (Ro-Neet)REI 48h, Group 15. For beets only. Apply 0.5-0.66 gal/A per application. Can be applied before, during, or immediately after planting. Apply in 10-50 gal/A of spray. Incorporate immediately 2-3” into the soil. Use on mineral soils only. Use the lower rate on sandy soils and the higher rate on silt and clay soils.

dimethenamid (Outlook): PHI 60d, REI 12h, Group 15. For beets only. Apply 8-21 oz/A, up to 2 applications allowed per year, a minimum of 14 days apart. Do not exceed 21 oz/A per year. If applying as a split application, apply half to two-thirds the rate at the first application and the remaining at the second application. Application rate depends on soil texture and organic matter content. Apply to beets that have 2 fully expanded true leaves, but not after they have 6 fully expanded leaves. Temporary leaf damage may occur and applying before the 2-leaf stage may cause significant crop injury.

s-metolachlor (Dual Magnum)REI 24h, Group 15. MASSACHUSETTS, MAINE, and NEW HAMPSHIRE only. Make sure the label for your state is available for download before using this product. This is a restricted label available only to growers who apply through the website www.syngenta-us.com/labels/indemnified-label-login(link is external) and agree to a waiver of liability. Main target weeds for this registration are galinsoga and yellow nutsedge. All label instructions will be supplied after the application for use is completed.

Postemergent Herbicides (after weeds germinate)

carfentrazone (Aim EC)PHI 0d, REI 12h, Group 14. Apply 0.5-2 oz/A per application, multiple applications allowed per year. Do not exceed 6.1 oz/A per year. Apply to row middles of emerged crops with hooded sprayers to control emerged weeds, including crops grown on mulch or plastic.  Prevent any spray from contacting the crop, or injury will occur.  For best results, make application to actively growing weeds up to 4” tall and rosettes less than 3” across. Can also apply up to 2 oz/A as a preplant burndown no later than 7 days before planting by seed for chard.

clethodim (Select Max)PHI 30d, REI 24h, Group 1. Apply 9-16 oz/A per application, up to 4 applications allowed per year, a minimum of 14 days apart. Do not exceed 64 oz/A per year.  Apply to actively growing grasses. Add 0.25% v:v nonionic surfactant (1 qt/100 gal of spray).  Can also be applied as a spot-spray by mixing 0.33-0.66% (0.44-0.85 oz/gal) Select Max and 0.25% v:v nonionic surfactant (0.33 oz/gal).  Spray to wet, but do not allow runoff of spray solution.

clopyralid (Stinger)PHI 30d, REI 12h, Group 4. For beets only. Apply 4-8 oz/A per application, up to 2 applications allowed per year. Do not exceed 8 oz/A per year. Apply when beets are in the 2- to 8-leaf stage and weeds are young and actively growing, between 2-4" tall. Spray additives are not recommended.

glyphosate (Roundup Power Max): PHI 14d, REI 4h, Group 9. Apply 10 oz to 3.1 qts/A per application, multiple applications allowed per year. Do not exceed 5 qts/A per year. Rate based on target weed species. Can be applied during fallow intervals, prior to planting or transplanting, at planting, or before crop has emerged. Could cause injury when applied prior to transplanting or direct-seeding into plastic mulch. Remove residual product from plastic mulch with a 0.5” of water through irrigation or rainfall prior to planting.

pelargonic acid (Scythe): PHI 1d, REI 12h, Group 0. Apply a 3-10% solution (3-10 gallons per 100 gallons of spray). Rate based on target weed species. Apply in 75-200 gal/A of spray or with a spot sprayer until foliage is wet but not to the point of runoff. Repeat applications as necessary. Can apply for vegetative burndown during site preparation, prior to crop emergence from soil, as a directed and shielded spray during crop growth taking care to avoid contact with foliage and green tissue of crops, or after harvest. For beets, can also apply as a harvest aid to remove crop leaves.

sethoxydim (Poast)PHI 60d for beets, 30d for chard, REI 12h, Group 1. For beets, apply up to 2.5 pt/A per application, multiple applications allowed per year, a minimum of 14 days apart. Do not exceed 5 pts/A per year. For chard, apply up to 1.5 pt/A per application, multiple applications are allowed, a minimum of 14 days between applications. Do not exceed 3 pts/A per year. Apply to actively growing grasses. Use with crop oil concentrate (2 pt/A) or methylated seed oil (1.5 pt/A). Note that crop oil can cause injury under hot and humid conditions. Can also be applied as a spot-spray by mixing 1-1.5% (1.3-1.9 oz/gal) Poast and 1% v:v crop oil concentrate (1.3 oz/gal). Spray to wet, but do not allow runoff of spray solution.