Weeds Pages
| Common name | Amount per acre | REI‡ | PHI‡ | |
|---|---|---|---|---|
| (Example trade name) | (hours) | (days) | ||
| Not all registered pesticides are listed. The following are listed alphabetically. When choosing a pesticide, consider information relating to environmental impact, resistance management, the pesticide's properties, and application timing. Tank mixes may be necessary to achieve desired control; see the Susceptibility of Weeds to Herbicide Control for information on specific weed control. Always read the label of the product being used. | ||||
| FALLOW | ||||
| A. | CAPRYLIC AND CAPRIC ACIDS | |||
| (Suppress EC)# | 6–9% (v/v) solution | 24 | NA | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: un | ||||
| COMMENTS: For nonselective burndown of weeds on winter beds. The smaller the weeds, the more effective the control. Low label rate of 3% not as effective as intermediate and higher rate. Thorough coverage is essential for effective control. Check with organic certifier to determine which products are organically acceptable. | ||||
| B. | GLYPHOSATE | |||
| (Roundup PowerMAX) | Label rates | 4 | NA | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: 9 | ||||
| COMMENTS: Rate depends on weed species. Controls most annuals and partially controls many perennials. Does not completely control burning nettle, field bindweed, little mallow, or nutsedge. Apply to emerged weeds on winter beds. Seed into undisturbed soil for maximum effectiveness. Adding ammonium sulfate often enhances control in areas with hard water. Manage Conyza spp. (fleabane and horseweed) biotypes that are resistant to glyphosate using herbicides with a different mode of action. | ||||
| C. | PARAQUAT* | 0.5–1.0 lb a.i. | ||
| (Gramoxone SL 2.0) | 2–4 pt | 12 | NA | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: 22 | ||||
| COMMENTS: For preplant, preemergence use on broccoli, cabbage, Chinese cabbage, cauliflower, or collard fields only. Apply to emerged weeds on winter beds; this contact herbicide will control many seedling weeds. Addition of a surfactant is essential for good control. Controls most emerged annual weeds and grasses and burns back perennial weeds. | ||||
| D. | PELARGONIC ACID | |||
| (Scythe) | Label rates | 12 | NA | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: 27 | ||||
| COMMENTS: For nonselective burndown of weeds on winter beds. The smaller the weeds, the more effective the control. | ||||
| PREPLANT (Direct-seeded crops) | ||||
| Before weeds emerge | ||||
| A. | BENSULIDE | 5–6 lb a.i. | ||
| (Prefar 4-E) | 5–6 qt | 12 | NA | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: 8 | ||||
| COMMENTS: Effective on a limited number of summer broadleaf and grass weeds. Not effective on volunteer grain crops. Apply preplant and mechanically incorporate 1 to 2 inches. Activate by drip or sprinkler irrigation. May be followed by sprinkler or furrow irrigation. Relatively insoluble in water and readily absorbs into organic matter, therefore leaching risks are low. Long residual period. | ||||
| B. | NAPROPAMIDE | 0.5–1.0 lb a.i. | ||
| (Devrinol DF-XT Selective) | 1–2 lb | 24 | NA | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: 15 | ||||
| COMMENTS: Registered for use only on broccoli, Brussels sprouts and cauliflower. Can be preplant incorporated or applied postplant in direct-seeded and transplanted cole crops, but best used on transplants. This herbicide must be used with care on direct-seeded cole crops to avoid injury. Use lower rate on coarse-textured soils. Activate by drip or sprinkler irrigation. Provides excellent control of all annual grasses, including volunteer cereals and a large number of broadleaf weeds (including chickweed). Napropamide has a long residual period and therefore can carry over and injure rotational crops; do not plant certain crops, especially cereal grains, lettuce, and sugarbeets, following its use in cole crops. | ||||
| C. | TRIFLURALIN | 0.5–0.75 lb a.i. | ||
| (Treflan HFP) | 1–1.5 pt | 12 | NA | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: 3 | ||||
| COMMENTS: Application rate varies by soil type. Effective on summer broadleaf and grass weeds. Preplant incorporation may be used for both direct-seeded and transplanted cole crops. Avoid use in cold, wet soils or under arid desert conditions. Must be mechanically incorporated 2 to 3 inches deep to remain effective. Can cause injury to cole crops under arid conditions in the southern desert and wet, cold winters in coastal areas (this herbicide is not widely used in these situations). Controls a limited spectrum of weeds (will control burning nettle) and has a long residual period. Residues may persist in the soil for up to 12 months, and are acutely harmful to sensitive crops, including corn, milo, spinach, and sugarbeet. | ||||
| PRETRANSPLANT | ||||
| Before weeds emerge | ||||
| A. | NAPROPAMIDE | 0.5–1.0 lb a.i. | ||
| (Devrinol DF-XT Selective) | 1–2 lb | 24 | NA | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: 15 | ||||
| COMMENTS: Registered for use only on broccoli, Brussels sprouts and cauliflower. This herbicide is safer to transplants than to direct-seeded cole crops. Use lower rate on coarse-textured soils. May be either preplant incorporated or applied after transplanting. Activate by drip or sprinkler irrigation. Provides excellent control of all annual grasses, including volunteer cereals and a large number of broadleaf weeds (including chickweed). Napropamide has a long residual period and therefore can carry over and injure rotational crops; do not plant certain crops (especially cereal grains, lettuce, and sugarbeets) following its use in cole crops. | ||||
| B. | OXYFLUORFEN | 0.125–0.5 lb a.i. | ||
| (Goal 2XL) | 1–2 pt | 24 | NA | |
| (GoalTender) | 0.5–1 pt | 24 | NA | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: 14 | ||||
| COMMENTS: Registered for pretransplant use for broccoli, cauliflower, and cabbage. Do not use on Brussels sprouts. Apply to preshaped beds. If weeds are present, add a surfactant to enhance weed kill. The high rate is especially useful for hard-to-control weeds such as little mallow. Do not disturb the soil after treatment except for the transplanting operation. At least 1/4-inch rainfall or irrigation is needed after application to activate the herbicide. Sufficient water movement from the drip line across the bed is needed to incorporate oxyfluorfen for optimum efficacy and crop safety. GoalTender provides good control of many broadleaf annual weeds (including burning nettle and little mallow), with the exception of chickweed. It is less effective at controlling large lambsquarters, mustards, and weedy grasses. Does not control yellow nutsedge. | ||||
| C. | TRIFLURALIN | |||
| (Treflan HFP) | Label rates | 12 | NA | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: 3 | ||||
| COMMENTS: Application rate depends on soil characteristics, the crop being grown, and whether the crop is transplanted or direct-seeded. Preplant incorporation may be used in both direct-seeded and transplanted cole crops. Preplant incorporate with rotary-powered equipment for bed planting; if planting flat (not on raised beds), shallow discing is acceptable. This herbicide is safer for transplanted cole crops than direct-seeded cole crops, but must be kept in the upper 2 to 3 inches of soil to minimize the chance of crop injury and maximize weed control. Will control burning nettle. | ||||
| AT PLANTING | ||||
| Before crop and weeds emerge | ||||
| A. | BENSULIDE | 5–6 lb a.i. | ||
| (Prefar 4-E) | 5–6 qt | 12 | 0 | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: 8 | ||||
| COMMENTS: Can be applied preplant or postplant preemergence (direct-seeded crops only), before the crop and weeds emerge. If applying after direct-seeding, apply as a surface application and follow immediately with irrigation. Relatively insoluble in water and readily absorbs into organic matter, therefore leaching risks are low. Long residual period. | ||||
| B. | NAPROPAMIDE | 0.5–1.0 lb a.i. | ||
| (Devrinol DF-XT Selective) | 1–2 lb | 24 | 0 | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: 15 | ||||
| COMMENTS: Registered for use only on broccoli, Brussels sprouts and cauliflower. Labeled for use in both direct-seeded and transplanted cole crops but is safer to transplants than to direct-seeded cole crops. May be either preplant incorporated or applied posttransplant (or postplant preemergence for direct-seeded crops) followed by sprinkler irrigation. Use lower rate on coarse-textured soils. Activate by drip or sprinkler irrigation. Provides excellent control of all annual grasses, including volunteer cereals and a large number of broadleaf weeds (including chickweed). Napropamide has a long residual period and therefore can carry over and injure rotational crops; do not plant certain crops (especially cereal grains, lettuce, and sugarbeets) following its use in cole crops. | ||||
| POSTPLANT | ||||
| After crop and weeds emerge | ||||
| A. | CAPRYLIC AND CAPRIC ACIDS | |||
| (Suppress EC)# | 6–9% (v/v) solution | 24 | 0 | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: un | ||||
| COMMENTS: For nonselective burndown of weeds. The smaller the weeds, the more effective the control. Low label rate of 3% not as effective as intermediate and higher rate shown above. Thorough weed coverage is essential for effective control. Use hooded sprayers or other equipment to avoid crop injury. Check with organic certifier to determine which products are organically acceptable. | ||||
| B. | CARFENTRAZONE | 0.016–0.032 lb a.i. | ||
| (Shark EW) | 1–2 fl oz | 12 | 0 | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: 14 | ||||
| COMMENTS: May be applied to the row middles using a hooded sprayer for control of some broadleaf weeds, including burning nettle, many cruciferous weeds, and little mallow. Take care to keep the spray off the crop. | ||||
| C. | CLETHODIM | 0.068–0.12 lb a.i. | ||
| (Select Max) | Annual grasses: 9–16 fl oz
Perennial grasses: 12–16 fl oz |
24 |
Head and stem crops: 30
Leafy crops: 14 |
|
| WSSA MODE-OF-ACTION GROUP NUMBER1: 1 | ||||
| COMMENTS: Selective postemergence herbicide for control of annual and perennial grass weeds including annual bluegrass. Always apply with a crop oil concentrate. Apply after the crop and weeds emerge. Controls seedlings of annual grasses (later stages of annual grasses are more difficult to control) and certain perennial grasses, but not broadleaf weeds or sedges. Less effective when grasses are moisture stressed. | ||||
| D. | SETHOXYDIM | 0.188–0.28 lb a.i. | ||
| (Poast) | 1–1.5 pt | 12 |
Mustard greens: 14
All others: 30 |
|
| WSSA MODE-OF-ACTION GROUP NUMBER1: 1 | ||||
| COMMENTS: Selective postemergence herbicide for control of annual and perennial grasses, except for annual bluegrass. Not effective on broadleaf weeds or sedges. Apply when grasses are small and actively growing. Do not cultivate within 5 days before or 7 days after application. An oil adjuvant is needed to achieve consistent weed control. Rotational grass crops (such as cereal grains and turf) are susceptible. To control volunteer cereals (barley, corn, oats, rye, and wheat) apply before tilling. | ||||
| E. | OXYFLUORFEN | 0.125–0.25 lb a.i. | ||
| (GoalTender) | Broadcast: 4–6 fl oz
Direct: 4–8 fl oz |
24 | 35 | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: 14 | ||||
| COMMENTS: For use on broccoli and cauliflower only as a broadcast postemergence application under a Special Local Needs Label (SLN No. CA-060023). Apply on direct-seeded crops when they have four true leaves, and to transplanted crops at least two weeks after planting. When properly applied, safe on transplanted broccoli or cauliflower. Can cause crop injury under cool, cloudy conditions and when the crop is stressed by other factors (see Special Local Needs label for more information). Do not apply with adjuvants or fertilizer, or tank-mix with other pesticides when applying postemergence. Controls emerged weeds such as little mallow, burning nettle, common purslane, nettleleaf goosefoot, and sowthistle, which are not burned back by fertilizer applications. GoalTender provides good control of many broadleaf annual weeds, with the exception of chickweed. It is less effective at controlling large lambsquarters, mustards, and weedy grasses. Does not control yellow nutsedge. | ||||
| F. | PELARGONIC ACID | |||
| (Scythe) | Label rates | 12 | 0 | |
| WSSA MODE-OF-ACTION GROUP NUMBER1: 27 | ||||
| COMMENTS: May be applied to the row middles using a hooded sprayer for nonselective burndown of annual weeds. The smaller the weeds, the more effective the control. Keep the spray off the crop to avoid crop injury. | ||||
| ‡ | Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of the two intervals is the minimum time that must elapse before harvest. |
| * | Permit required from county agricultural commissioner for purchase or use. |
| # | Acceptable for use in organically grown produce. |
| 1 | Group numbers are assigned by the Weed Science Society of America (WSSA) according to different modes of action. Although weeds may exhibit multiple resistance across many groups, use mode-of-action group numbers to plan mixtures or rotations of herbicides with different modes of action. |
| NA | Not applicable. |