NOTE: For the herbicides listed below, one product trade name and formulation is provided for each active ingredient as an example of rates, preharvest interval (PHI), restricted entry interval (REI), resistance management group number, 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.
- glyphosate (Roundup Power Max): REI 12h, Group 9.
- paraquat (Gramoxone SL 2.0*): REI 12h, Group 22. Use 2 – 4 pts/A. Include a nonionic surfactant at 0.25% v/v, or crop oil concentrate/methylated seed oil at 1.0% v/v (1 gal/100 gal) of the finished spray volume for maximum efficacy. May be fatal if swallowed or inhaled. *Restricted use: Applicators must complete an EPA-approved paraquat training every 3 years: https://www.epa.gov/pesticide-worker-safety/paraquat-dichloride-training-certified-applicators.
- pelargonic acid (Scythe): PHI 1d, REI 12h, Group 17.
Preemergent Herbicides (before weeds germinate)
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clomazone (Command 3ME): REI 12h, Group 13. Apply 21.3 oz/A per application, only 1 application per year. Apply to the soil surface after seeding but before crop emergence. Apply in a minimum 10 gal/A of spray. Place seed below the chemical barrier when planting. Some temporary crop injury (partial whitening of leaf or stem tissue) may be visible after crop emergence. Complete recovery will occur from minor early injury without affecting yield or earliness.
- linuron (Lorox DF): REI 24h or 8d, Group 5. Apply 2 lbs/A per application, only 1 application per year. Apply after planting but before crop emergence. Use the lower rate on sandy soils adn the higher rate on silt and clay soils. Do not apply to field peas used for livestock feed. Incorporate into the soil with water through irrigation or rainfall.
- pendimethalin (Prowl H2O): PHI 60d, REI 24h, Group 3. Apply 1.5-3 pts/A per application, only 1 application per year. Apply before planting and incorporate 2-3” into the soil. Do not bring untreated soil to the surface. Activate with water through rainfall or irrigation.
- s-metolachlor (Dual Magnum): REI 24h, Group 15. Shelling peas and dry peas only. Apply 1-2 pt/A per application, multiple applications allowed per year, a minimum of 14 days apart. Do not exceed 2 pt/A per year. Reduce soil movement after application for improved weed control. The combined applications in the fall plus spring must not exceed the maximum allowed annual rate. Has not been tested on all varieties; crop tolerance should be verified before treating the entire field. Can be applied after planting but before crop emerges, or after the 1st trifoliate stage of bean growth, although leaf spotting may occur. Can also be applied within 14 days of planting and incorporates 2” into the soil. Apply and incorporate after bed formation if planting into beds. The risk of crop injury is greater on light-textured soils and under cool wet conditions, and may delay maturity and reduce yield. Rate based on soil texture and organic matter.
- sulfentrazone (Aquesta 4F): REI 12h, Group 14. Apply 2.25-6 oz/A per application, only 1 application per year. Apply as a before crop has emerged in a minimum of 10 gal/A of spray. Do not incorporate. Planting less than 1” into the soil, inadequate seed furrow closure, or poor growing conditions can cause adverse crop response. Wait a minimum of 7 days after application to plant in coarse-textured soils with less than 1.5% organic matter. Reduce rate on coarse-textured soil with organic matter less than 1.5% and pH of 7.8 or higher, or on highly eroded soils, or in areas of calcareous outcroppings to minimize adverse crop response.
- trifluralin (Treflan HFP): REI 12h, Group 3. Shelling peas. Apply 1-1.5 pt/A per application, only 1 application per year. Apply before planting and incorporate 2-3” into the soil of the final seedbed within 24 hours of application. Disc twice after spraying for satisfactory incorporation. Rate depends on soil texture.
Pre- and Postemergent Herbicides
- imazethapyr (Pursuit): PHI 30d, REI 4h, Group 2. Shelling peas and dry peas. Apply up to 3 oz/A per application. Apply within 1 week of planting or up to 3 days after planting. Incorporate into the soil if applying before planting. Can also be applied when peas are 3” tall but before 5 nodes or flowering. Nonionic surfactant must be added to the spray solution for postemergent use.
- metribuzin (Metribuzin): PHI 50d, REI 12h, Group 5. Apply 0.25-0.5 lb/A per application. Do not exceed 0.6 lb/A per year. Can be applied in a single preemergent application 0.25-0.5 lb/A in at least 10 gal/A of spray. Apply before or after planting. Incorporate 1-2” into the soil with cultivation or water through rainfall irrigation. One post-emergent broadcast application may be made per season when weeds are less than 2’’ tall or wide and before crop is 6’’ tall. For spring peas, apply 0.16-0.3 lb/A and for winter peas, apply 0.25-0.3 lb/A. Apply in a minimum of 20 gal/A of spray.
- saflufenacil (Sharpen): PHI 3d, REI 12hr, Group 14. Apply 1-2 oz/A per application, multiple applications allowed per year, a minimum of 30 days apart. Do not exceed 2 oz/A per year. Can be applied up to 3 days after planting but before cracking stage or emergence of peas. Ensure the seed row is closed, or severe crop injury will occur. Do not incorporate. Can also be applied 1 week before planting and incorporated less than 3” into the soil. Can also be applied post emergent in a minimum of 10 gal/A of spray. May also be used as a harvest aid/desiccant for dried field peas. When used as a desiccant, the application does not contribute to the maximum cumulative seasonal use rate for a crop. Spray over the top of dry peas that have reached physiological maturity (peas with at least 80% yellow/brown pods and no more than 30% of leaves still green for vine-type peas, and no more than 40% of leaves still green for bush-type peas). Allow up to 10 days for optimum desiccation effect. Has not been tested on all varieties, crop tolerance should be verified before treating the entire field. Do not use for green lentils. Plant legumes at least 0.5” deep to reduce risk of crop injury. May result in delayed crop emergence and stunting in cool wet conditions after application.
Postemergent Herbicides (after weeds germinate)
- bentazon (Basagran): PHI 10d for succulent peas, 30d for dry peas, REI 48h, Group 6. Apply 0.8-1.6 pt/A per application. Do not exceed 3.2 pt/A per year. Rate based on weed composition. Apply to actively growing weeds.Apply after 3 pairs of leaves (or 4 nodes) are present. An effective treatment in an emergency situation to control certain broadleaf weeds and fairly effective against yellow nutsedge when 4-6" tall. Pea injury such as yellowing, bronzing, speckling, or burning of leaves may occur under certain conditions. Temporary injury is generally outgrown without delay of podset, maturity or reducing yields. Do not apply when peas are in bloom or under stress from root rot. Do not apply with a crop oil concentrate or injury and yield reductions may occur.
- carfentrazone (Aim EC): 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. Can be applied as a preplant burndown no later than 1 day before planting. Can also be applied to row middles of emerged crops with hooded sprayers to control emerged weeds. 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.
- clethodim (Select Max): PHI 21d, REI 24hr, Group 1. Apply 9-16 oz/A per application, only 1 application per year. Apply before bloom. Add 0.25% v:v nonionic surfactant (1 qt/100 gal of spray). Can also be used as a spot-spray by mixing 0.33-0.66% (0.44 to 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.
- glyphosate (Roundup PowerMax): PHI 7d, REI 4hr, Group 9. Apply 15 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, before crop has emerged, or as a spot treatment. Only 1 spot treatment application allowed per year. Do not combine spot treatment and preharvest applications on the same crop. 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.
- imazamox (Raptor): REI 4h, Group 2. Apply up to 3 oz/A per application, only 1 application per year. Apply when peas are at least 3” tall but before 5 nodes or flowering. A nonionic surfactant must be added to the spray solution. Apply at least 1 hour before rainfall or overhead irrigation. Rate based on weed composition. For English peas, some varieties are more sensitive than others, and use may delay maturity or reduce crop growth, quality, or yield. Has not been tested on all varieties; crop tolerance should be verified before treating the entire field.
- paraquat (Gramoxone SL 3.0*): REI 12h or 24h (based on application type), Group 22. Apply 1.3-2.7 pts/A per application, up to 3 applications allowed per year, a minimum of 7 days apart. Do not exceed 8 pts/A per year. Apply before, during, or after planting, but before emergence as a banded or broadcast application in a minimum of 10 gal/A of spray. Minimize soil disturbance when seeding. May be fatal if swallowed or inhaled. *Restricted use: Applicators must complete an EPA-approved paraquat training every 3 years: https://www.epa.gov/pesticide-worker-safety/paraquat-dichloride-training-certified-applicators.
- pelargonic acid (Scythe): PHI 1d, REI 12h, Group 0. Apply a 3-10% solution (3-10 gal/100 gal). 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.
- quizalofop (Assure II): PHI 60d dry, 30d succulent, REI 12h, Group 1. Apply up to 4-12 oz/A per application, up to 2 applications allowed per year, a minimum of 7 days apart. Do not exceed 14 oz/A per year. Rate based on weed composition and growth stage. Apply with either crop oil concentrate or non-ionic surfactant. Do not apply when crop or weeds are under drought stress.
- sethoxydim (Poast): PHI 30d dry, 15d succulent, REI 12h, Group 1. Apply up to 2.5 pt/A per application, multiple applications allowed per year, a minimum 14 days apart. Do not exceed 4 pt/A per year. Use with crop oil concentrate (2.0 pt/A) or methylated seed oil (1.5 pt/A). Crop oil can cause injury under hot and humid conditions. Can also be used as a spot-spray by mixing 1-1.5% (1.3-1.9 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.