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.
Herbicides Used Preemergence, before weeds germinate
pendimethalin (Prowl H2O): PHI 60 or 200 d (based on rate), REI 24h, Group 3. Must be applied at least 1 to 2 days before transplanting artichoke. Apply up to 3 pt/A so soil surface for 60 day PHI, or a higher rate of 3.1 to 8.2 pt/A can be used but requires a 200 day PHI.
Herbicides Used for Pre- and Postemergence Weed Control
oxyfluorfen (Goal 2 XL): PHI 5d, REI 48h, Group 14. Used for both pre- and postemergence weed control. Apply 4 to 6 pt/A as a directed spray to the soil surface between the rows and at the base of artichoke plants. Do not apply over-the-top. Contact with direct spray or drift will cause injury to artichoke fronds or severe injury to buds or flowers. Do not apply more than 6 pints of Goal 2XL per acre per season as a result of a single application or multiple applications.
Herbicides Used Postemergence, after weeds germinate
clethodim (Select Max): PHI 5d, 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 64 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.
paraquat (Gramoxone SL 2.0*): REI 12h, Group 22. For use between rows after crop establishment. Apply up to 2.5 to 4 pt/A as a directed and shielded spray to emerged weeds between rows when weeds are succulent and weed growth is less than 6”. Maximum 3 applications per year, not to exceed a total of 8 pt/A per season. Use precision directed spray application equipment adjusted to prevent spray contact with crop plants. Crop contact by the spray will cause severe injury or death. Do not exceed 30 psi nozzle pressure or spray under conditions which may cause excessive drift.
sethoxydim (Poast): PHI 7d, REI 12h, Group 1. Controls grass weeds only. Apply to actively growing grasses (see product label for susceptible stage). Maximum 2.5 pt/A per application, minimum 14-days between applications. Do not exceed 5 pt/A per year. Use with crop oil concentrate (2.0 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 used as a spot-spray by mixing 1-1.5% (1.3 to 1.9 oz per gallon) Poast and 1% v:v crop oil concentrate (1.3 oz per gallon). Spray to wet, but do not allow runoff of spray solution.