Weed Control

NOTE:  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. 

See section Soil Fumigation Outdoors (page 89). Proper use of Vapam can provide weed control and will be more economical if multiple plantings are used.

Stale Seedbed

See Stale Seedbed Technique (page 107).

glyphosate (Roundup Power Max): REI 12h, Group 9.

pelargonic acid (Scythe): PHI 1d, REI 12h, Group 17. Use a 3 -10% solution (3 to 10 gallons per 100 gallons).

Herbicides Used Preemergence to Weeds

trifluralin (Treflan HFP): REI 12h, Group 3. Apply 1 to 1.5 pt/A as a preplant soil incorporated treatment. Select rate based on soil texture; see label for details.  Must be incorporated into the top 2 to 3 inches of the final seedbed within 24 hours of application.  Disc twice after spraying for satisfactory incorporation. See label for info on incorporation recommendations based on different equipment and single pass incorporation. Especially effective for annual grass.

Herbicides Used Postemergence to Weeds

carfentrazone (Aim EC): REI 12h, Group 14.  Aim is a burndown herbicide and will injure any foliage it comes into contact with. Apply Aim 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 inches tall and rosettes less than 3 inches across. Good coverage is essential for good control.  Apply up to 2 oz/A per application, and do not exceed a total of 6.1 oz/ per season. 

clethodim (Select Max): PHI 15d, REI 24h, Group 1.  Will control grass weeds only. Apply to actively growing grasses.  See label for rate selection.  Multiple applications permitted of 9 to 16 oz/A per application, minimum 14-days between applications, not to exceed 32 oz/A per year.  Add 0.25% v:v nonionic surfactant (1 qt per 100 gal of spray).  Can also be used as a spot-spray by mixing 1/3-2/3% (0.44 to 0.85 oz per gallon) Select Max and 0.25% v:v nonionic surfactant (0.33 oz per gallon).  Spray to wet, but do not allow runoff of spray solution.

pelargonic acid (Scythe):  PHI 1d, REI 12h, Group 17. Use a 3 -10% solution (3 to 10 gallons per 100 gallons). Use a 3 to 5% solution for annual weeds, a 5 to 7% solution for biennial and perennial weeds, and 7 to 10% solution for maximum burndown. Delivery rate for boom applications should be 75 to 200 gals 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. See label for complete details.