Pretransplant, Preemergence, or Post-directed

carfentrazone (Aim EC)

Transplants only

Rate Up to 0.031 lb ai/a (2 fl oz Aim EC)

Time Apply up to 1 day before transplanting.

Remarks Tank-mixes with other herbicides increase spectrum of control. Apply to actively growing weeds not more than 4 inches tall or rosettes 3 inches in diameter. Contact activity only. Coverage is essential for good control.

Caution Do not exceed 0.031 lb ai/a (2 fl oz Aim EC) per crop season.

Site of action Group 14: protoporphyrinogen oxidase inhibitor

Chemical family Triazinone

clomazone (Command 3ME)

Peppers only, but not on banana peppers

Rate 0.25 to 1 lb ai/a (0.66 to 2.66 pints/a). Use lower rates on coarse soil, higher rates on fine soils.

Time Preemergent soil-applied, before transplanting.

Remarks Place roots below the chemical barrier when planting. Do not use on banana peppers.

Caution Clomazone has a residual or carryover of up to 16 months. Therefore, consult label for rotational crops before applying. Do not apply next to sensitive crops when there is potential for drift. The microencapsulated (ME) formulation is designed to minimize drift and injury to adjacent fields and sites.

Site of action Group 13: inhibits DOXP synthase

Chemical family Isoxazolidinone

DCPA (Dacthal)

Tomatoes and eggplant only

Rate 4.5 to 10.5 lb ai/a (6 to 14 lb/a), depending on soil type.

Time Apply 4 to 6 weeks after transplanting to moist, weed-free soil; apply more water to activate.

Remarks Performs poorly in western Oregon and Washington. Consult label for planting sensitive crops within 12 months. Results can be improved with overhead irrigation immediately after spraying. Inhibits mitosis.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Phthalic acid

halosulfuron (Sandea)

Consult label for crop-specific instructions

Rate 0.023 to 0.047 lb ai/a (0.5 to 1 oz/a)

Time In tomatoes: apply pretransplant on bare ground or under plastic mulch, 7 days before transplanting. Post-transplant before tomato bloom.

Remarks Controls nutsedge and other broadleaf weeds. Postemergence applications are usually more effective than preemergence applications on nutsedge. May be used under plastic mulch in tomatoes. May only be applied between rows for pepper and eggplant.

Caution Sandea-treated soil in transplant hole may injure crop. Note crop rotation intervals. Not all pepper varieties have been tested.

Site of action Group 2: acetolactate synthase (ALS) inhibitor

Chemical family Sulfonylurea

metribuzin (Tricor 4F)

Tomatoes only, but not direct-seeded

Rate 0.25 to 0.5 lb ai/a (0.5 to 1 pint/a)

Time Preplant incorporate before transplanting.

Remarks Use lower rates on soils with 0.5% to 2% organic matter, but do not use on soils with less than 0.5% organic matter. Inhibits photosynthesis.

Caution Do not exceed 1 lb ai/a per season.

Site of action Group 5: photosystem II inhibitor

Chemical family Triazinone

napropamide (Devrinol)

Tomatoes and pepper: direct-seeded or transplant; Eggplant: transplant only

Rate Tomatoes and peppers: 1 to 2 lb ai/a (2 to 4 lb/a Devrinol 50DF); Eggplants: 1 to 2 lb ai/a (2 to 4 quarts/a Devrinol 2-XT)

Time Apply to a weed-free soil surface and incorporate uniformly 1 to 2 inches deep before transplanting. Use lower rates on light, sandy, or coarse soils.

Remarks After harvest, plow deeply with moldboard or disk plow before planting succeeding crops. Inhibits seedling roots.

Site of action Group 15: inhibits very long chain fatty acid synthesis

Chemical family Acetamide

pendimethalin (Prowl H2O only)

Rate 0.475 to 1.43 lb ai/a (1 to 3 pints/a) depending on soil type.

Time Preplant incorporate before transplanting; preplant surface apply before transplanting; or post-directed application to transplanted or established direct-seeded tomatoes, peppers, and eggplant.

Remarks Spray only once and avoid overlaps. Use lower rates on light or coarse soils low in organic matter. Consult label for planting crops within 12 months. Direct sprays to soil beneath transplants if applying postemergence. Inhibits mitosis, primarily in shoots. Preharvest interval is 21 days for tomatoes and 70 days for peppers and eggplant.

Caution Do not apply to direct-seeded tomatoes or over the top of tomatoes, as injury will be severe. Consult crop injury disclaimer on label before using.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Dinitroaniline

rimsulfuron (Matrix)

Field-grown tomatoes only

Rate 0.5 to 1 oz ai/a (2 to 4 oz/a) preemergence

Time Apply after seeding or transplanting.

Remarks Must be activated by rainfall or irrigation (0.5 to 1 inch) within 5 days, regardless of soil moisture at planting. If activation with water is not possible it may be best to wait until weeds have emerged to apply Matrix postemergence. Tomato varieties may differ in tolerance to rimsulfuron; apply to a small test area before treating whole fields.

Caution Consult label for adjuvant recommendations.

Site of action Group 2: acetolactate synthase (ALS) inhibitor

Chemical family Sulfonylurea

S-metolachlor (Dual Magnum, Charger Basic, or Brawl)

Supplemental label; tomatoes only

Rate 0.95 to 1.9 lb ai/a (1 to 2 pints/a) depending on soil texture and organic matter content

Time Pretransplant incorporated, pretransplant on the surface, or postdirected to transplanted tomatoes at least 4 inches tall.

Remarks If applied pretransplant, incorporate but to less than the depth of transplanting. Postdirected applications to transplanted tomatoes should be after the first irrigation or settling rain. S-metolachlor will not control emerged weeds.

Caution Do not apply to varieties or cultivars with unknown tolerance to S-metolachlor. S-metolachlor may damage transplants weakened for any reason. Do not plant under wet, cool, or unfavorable growing conditions. Preharvest interval is 90 days if single application rate ≥1.33 pints/a; 30 days if <1.33 pints/a. Use of adjuvants is prohibited in tomatoes.

Site of action Group 15: inhibits very long-chain fatty acid synthesis

Chemical family Chloroacetamide

S-metolachlor (Dual Magnum)

Transplanted bell peppers, Oregon only
Do not apply to direct-seeded crops

Rate Before transplanting: 0.48 to 0.96 lb ai/a (0.5 to 1 pint/a Dual Magnum); after transplanting: 0.96 to 1.6 lb ai/a (1 to 1.67 pints/a Dual Magnum). Use lower rates on coarse soil and higher rates on fine-texture soil. In most Willamette Valley soils, if used according to label, 1 pint/a gives acceptable weed control with minimal phytotoxicity concerns.

Time Before and after transplanting (do not incorporate).

Remarks Special local needs label OR-070004. Transplanted bell peppers are very tolerant to over-the-top broadcast applications of S-metolachlor. Do not add adjuvants of any kind. Will not control emerged weeds; till the soil 2 to 3 days before applying to destroy weeds that may have emerged. Weed control is best if applied after transplanting and if about 0.5 inch of irrigation water is applied shortly after transplanting (up to 2 days).

Caution Ensure that S-metolachlor-treated soil is not concentrated near bell pepper roots during transplanting, by minimizing the amount of S-metolachlor-treated soil allowed into the furrow during planting. S-metolachlor may injure crops if plant roots directly contact treated soil. Muck soils (more than 20% organic matter) normally require the higher rate (1 pint/a); however, weed control may be reduced on muck soils. Apply only once per crop; do not exceed 1 pint/a. Do not apply and incorporate S-metolachlor before transplanting. Preplant-incorporated applications may injure the crop. Tank mixing with other herbicides may increase the chance of crop injury. Preharvest interval is 60 days.

Site of action Group 15: inhibits very long-chain fatty acid synthesis

Chemical family Chloroacetamide

sulfentrazone (Spartan)

Transplanted tomatoes only

Rate 0.125 to 0.25 lb ai/a (3.25 to 8 oz/a Spartan) depending on soil OM and soil texture class.

Time Apply pre-transplant, and prior to weed emergence.

Remarks Irrigation or rainfall is needed to activate this herbicide. Irrigation of 0.5 to 1 inch is typically sufficient and will occur. Excess irrigation should be avoided. Do not use on coarse, sandy soils with less than 1% organic matter. Experience lacking in the PNW for this use.

Caution Note significant rotation intervals, including 24 months for canola and 36 months for sugar beets.

Site of action Group 14: protoporphyrinogen oxidase (PPO) inhibitor

Chemical family Triazolinone

trifluralin (Treflan)

Transplants only

Rate 0.5 to 1 lb ai/a (1 to 2 pints/a) depending on soil type and crop

Time Apply before transplanting peppers and before or after transplanting tomatoes or eggplant. Incorporate within 24 hours by cross-disking or by using a power take-off (PTO) rotary tiller.

Remarks Spray only once and avoid overlaps. Use lower rates on light or coarse soils low in organic matter. Consult label for planting crops within 12 months. Direct sprays to soil beneath transplants if applying postemergence. Inhibits mitosis, primarily in shoots.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Dinitroaniline