Tank-Mixtures

Note: Not all tank-mixtures labeled for use in potatoes are listed. See the potato herbicide labels for other allowed tank-mixtures. Read and follow applicable "Restrictions and Limitations and Directions for Use" on all product labels in a tank-mixture. The most restrictive labeling applies to use of tank-mixtures.

EPTC (Eptam) + metribuzin (Metribuzin 4L or others, 4 lb ai/gal; or Metribuzin 75; TriCor DF or others, 75%)

Rate 3.5 pints/a Eptam on coarse soils or 4.5 pints/a Eptam on fine-texture soils + 0.5 to 1 pint/a 4L or 0.33 to 0.67 lb/a 75%

Time May apply before planting; during or after hilling, when applied postemergence and broadcast by ground, until potatoes are 4 inches tall; or, when applied through a sprinkler irrigation system, until potatoes are 6 inches tall. Thoroughly incorporate the tank-mixture into top 2 to 3 inches of soil mechanically or by sprinkler irrigation.

Remarks Use lower rates on coarse soils. Incorporate immediately after application. When metered into irrigation systems, use 0.5 to 0.75 inch of water/a with a center pivot system. For solid-set wheel lines or hand lines, apply herbicide mixture in 0.5 to 1 inch of water. For best results, wet soil 3 to 4 inches deep during chemigation. See previous entries in this section for application and incorporation methods, remarks, cautions, and re-cropping and rotational cropping restriction information for these herbicides.

Caution See previous entries in this section for potato variety sensitivity to metribuzin. In general, do not apply this tank-mixture postemergence to early-maturing, smooth-skinned, white-skinned, or red-skinned varieties of potato.

Site of action (EPTC) Group 8: lipid synthesis inhibitor but not an ACCase inhibitor; (metribuzin) Group 5: photosystem II inhibitor

Chemical family (EPTC) thiocarbamate; (metribuzin) triazinone

pendimethalin (Prowl (3.3 EC or Prowl H2O) + EPTC (Eptam)

Rate 1.2 to 2.4 pints/a Prowl 3.3EC or 1.5 to 3 pints/a Prowl H2O + 3.5 to 7 pints/a Eptam

Time Apply after planting but before potatoes and weeds emerge.

Remarks Use lower rates on coarse soils and higher rates on finer, heavier soils. The tank-mixture will not control emerged weeds.

Caution Follow Prowl 3.3 EC or Prowl H2O and Eptam labels' most restrictive directions, timing, limitations, precautions, and restrictions on use in potatoes. See the previous sections in this chapter for application and incorporation methods, remarks, cautions, and recropping and rotational cropping restriction information for these herbicides.

Site of action (pendimethalin) Group 3: microtubule assembly inhibitor; (EPTC) Group 8: lipid synthesis inhibitor but not an ACCase inhibitor

Chemical family (pendimethalin) Dinitroaniline; (EPTC) Thiocarbamate

pendimethalin (Prowl 3.3EC or Prowl H2O) + metribuzin (Metribuzin 4L or others, 4 lb ai/gal; or Metribuzin 75; TriCor DF or others, 75%)

Rate Preemergence: use 1.2 to 3.6 pints/a Prowl 3.3EC or 1.5 to 3 pints/a Prowl H2O + 1 to 2 pints/a metribuzin 4 or 0.67 to 1.33 lb/a metribuzin 75%DF. Early postemergence: use 1.2 to 3.6 pints/a Prowl 3.3EC or + 0.5 to 1 pint/a metribuzin 4 or 0.33 to 0.67 lb/a metribuzin 75%DF.

Time Apply as a tank-mix, after planting up to the 6-inch stage of potato growth. Mixture also may be applied through sprinkler systems.

Remarks Use lower rates on coarse soils. About 0.5 inch of overhead moisture is needed to move herbicides into sandy soils and up to 0.9 inch into silt-loam soils. For best control, apply before weeds are 1 inch tall. See the previous entries in this section for application and incorporation methods, remarks, cautions, and re-cropping and rotational cropping restriction information for these herbicides.

Caution Do not apply within 24 hours of applying other pesticides. Do not mechanically incorporate this combination into soil; doing so decreases weed control and may injure potatoes. See the previous entries in this section for potato variety sensitivity to metribuzin. In general, do not apply this tank-mixture postemergence to early-maturing, smooth-skinned, white-skinned, or red-skinned varieties of potato.

Site of action (pendimethalin) Group 3: microtubule assembly inhibitor; (metribuzin) Group 5: photosystem II inhibitor

Chemical family (pendimethalin) dinitroaniline; (metribuzin) triazinone

pendimethalin (3.3EC or Prowl H2O) + metribuzin (Metribuzin 4L or others, 4 lb ai/gal; or Metribuzin 75; TriCor DF or others, 75%) + EPTC (Eptam)

Rate 1.2 to 2.4 pints/a Prowl 3.3EC or 1.5 to 4 pints/a Prowl H2O + 0.5 to 1 pint/a metribuzin 4, or 0.33 to 0.67 lb/a metribuzin 75%DF + 3 to 3.5 pints/a Eptam

Time Apply with ground equipment or through sprinkler irrigation systems, as a tank-mix after planting but before potatoes and weeds emerge. Mixture also may be applied through sprinkler systems postemergence, from crop emergence up to 6-inch stage of potato growth.

Remarks Use lower rates on coarse soils. Tank-mix will not control established weeds; destroy them before application. See the previous entries in this section for application and incorporation methods, remarks, cautions, and re-cropping and rotational cropping restriction information specific to these herbicides.

Caution Do not use on peat or muck soils. Do not apply if potatoes are stressed from cold and wet or hot and dry conditions, or crop may be injured. See previous entries in this section for potato variety sensitivity to metribuzin. In general, do not apply this tank-mixture postemergence to early-maturing, smooth-skinned, white-skinned, or red-skinned varieties of potato.

Site of action (pendimethalin) Group 3: microtubule assembly inhibitor; (metribuzin) Group 5: photosystem II inhibitor; (EPTC) Group 8: lipid synthesis inhibitor but not an ACCase inhibitor

Chemical family (pendimethalin) Dinitroaniline; (metribuzin) Triazinone; (EPTC) Thiocarbamate

rimsulfuron (Matrix SG; Matrix FNV; Solida; and others, 25%) + metribuzin (Metribuzin 4L or others, 4 lb ai/gal; or Metribuzin 75; TriCor DF or others, 75%)

Rate Preemergence: use 1 to 1.5 oz/a rimsulfuron + 0.5 to 1.125 pint/a metribuzin 4 or 0.33 to 0.75 lb/a metribuzin 75%DF. Postemergence: use 1 to 1.5 oz/a rimsulfuron + 0.5 to 1 pint/a metribuzin 4 or 0.33 to 0.67 lb/a metribuzin 75%DF. Use a nonionic surfactant at 0.125% v/v (1 pint/100 gal) if weeds have emerged.

Time After planting or dragoff but before crop and weeds emerge, or postemergence when weeds are small (less than 1 inch high or across for most species).

Remarks This tank-mixture can improve control of common lambsquarters, Russian thistle, kochia, and wild buckwheat better than rimsulfuron alone. The mixture also is an effective resistance-management tool for ALS-inhibitor-resistant species that are controlled by metribuzin and for triazine-resistant species that are controlled by rimsulfuron. Rimsulfuron + metribuzin controls hairy nightshade but not cutleaf nightshade. When both hairy and cutleaf nightshade infest a field, tank mix rimsulfuron + metribuzin with Eptam or Dual Magnum or other potato herbicides controlling cutleaf nightshade in order to control both species. If a split application is used (preemergence + postemergence or postemergence + postemergence), do not exceed a total of 0.039 lb ai/a (2.5 oz/a 25%DF) rimsulfuron. Follow the metribuzin label recommendations on rates for split applications. See previous entries in this section for application and incorporation methods, remarks, cautions, and re-cropping and rotational cropping restriction information for these herbicides.

Caution See previous entries in this section for potato variety sensitivity to metribuzin. In general, do not apply this tank-mixture postemergence to early-maturing, smooth-skinned, white-skinned, or red-skinned varieties of potato. Using crop oil concentrate or methylated seed oil adjuvants is not recommended with the rimsulfuron + metribuzin tank-mix postemergence. Applied postemergence, this mixture may temporarily yellow potato foliage. Under environmental stress (cool, wet, or hot or humid weather), this mixture applied postemergence also may cause leaf malformations and stunted growth. Potatoes recover within 7 to 15 days. To reduce potential injury, apply mixture only if the weather has been sunny for at least 3 successive days. Do not use on seed potatoes unless permitted by a supplemental label. Apply postemergence before potatoes are 14 inches tall and before June 30. Do not apply within 60 days of harvest.

Site of action (rimsulfuron) Group 2: acetolactate synthase (ALS) inhibitor; (metribuzin) Group 5: photosystem II inhibitor

Chemical family (rimsulfuron) Sulfonylurea; (metribuzin) Triazinone

rimsulfuron (Matrix SG; Matrix FNV; Solida; or others, 25%) + EPTC (Eptam)

Rate 1 to 1.5 oz/a rimsulfuron + 3.5 to 7 pints/a Eptam

Time Apply preemergence before potatoes and weeds emerge and after dragoff or hilling. To avoid placing rimsulfuron too deep, incorporate the tank-mix with sprinkler irrigation rather than machinery. Apply postemergence, before potatoes are 4 to 6 inches tall, with a nonionic surfactant at 0.125% v/v (1 pint/100 gal spray solution) if weeds have emerged. This tank-mixture may be applied preemergence or early postemergence through chemigation. If your area does not allow sprinkler irrigation incorporation, then apply Eptam and rimsulfuron in a split application. (Semi-arid regions of Idaho, Oregon, and Washington allow sprinkler irrigation incorporation.)

Remarks Tank-mix controls crabgrass, hairy nightshade, cutleaf nightshade, and common lambsquarters more effectively than rimsulfuron alone. A three-way mixture of rimsulfuron + Eptam + Dual Magnum or of rimsulfuron + Eptam + Prowl 3.3 EC or H2O may be used after planting but before potatoes and weeds emerge. See the previous entries in this section for application and incorporation methods, remarks, cautions, and re-cropping and rotational cropping restriction information for these herbicides.

Caution Applied postemergence, rimsulfuron + Eptam may temporarily yellow potato foliage. Under environmental stress (cool, wet, or hot or humid weather), mixture applied postemergence also may stunt growth and cause leaf malformations. Potatoes recover within 7 to 15 days. To reduce injury, apply mixture only if the weather has been sunny at least 3 successive days. Do not use on seed potatoes unless permitted by a supplemental label.

Site of action (rimsulfuron) Group 2: acetolactate synthase (ALS) inhibitor; (EPTC) Group 8: lipid synthesis inhibitor but not an ACCase inhibitor

Chemical family (rimsulfuron) Sulfonylurea; (EPTC) Thiocarbamate

rimsulfuron (Matrix SG; Matrix FNV; Solida; or others, 25%) + EPTC (Eptam at a reduced rate) + MSO or OS/MSO + AMS

Postemergence

Rate 1 to 1.5 oz/a rimsulfuron + 1 pint/a Eptam

Time Apply postemergence. Include either 1% v/v (1 gal/100 gal spray mix) of a methylated seed oil (MSO) or 0.5% v/v (0.5 gal/100 gal spray mix) of an organosilicone modified adjuvant (OS/MSO). Also include 2 lb/a of a spray-grade ammonium sulfate (AMS). This tank-mixture may be applied early postemergence through chemigation.

Remarks For best results, rain or sprinkler irrigation is needed no sooner than 4 hours but not more than 1 day after application. Rain or irrigation should be 0.33 to 1 inch depending on soil texture: in sandy soils, apply at least 0.33 inch; in sandy loam soils at least 0.5 inch; in silt soils at least 0.75 inch; and in clay soils at least 1 inch. Additional Eptam can be chemigated during the sprinkler incorporation process if desired. Read and follow all use directions, restrictions, and precautions on Eptam 7E label before use. If Eptam label conflicts with this rimsulfuron label, do not use Eptam as a tank-mix partner as described in this section. See the previous entries in this section for application and incorporation methods, remarks, cautions, and re-cropping and rotational cropping restriction information for these herbicides.

Caution This tank-mixture may cause leaf burn and temporary yellowing if applied in hot weather. Adding fungicides may increase the level of crop injury. In warm, moist weather, the expression of herbicide symptoms is accelerated; in cold, dry weather, expression of herbicide symptoms is delayed and may be more variable in weed control.

Site of action (rimsulfuron) Group 2: acetolactate synthase (ALS) inhibitor; (EPTC) Group 8: lipid synthesis inhibitor but not an ACCase inhibitor

Chemical family (rimsulfuron) Sulfonylurea; (EPTC) Thiocarbamate

rimsulfuron (Matrix SG; Matrix FNV; Solida; or others, 25%) + metribuzin (Metribuzin 4L or others, 4 lb ai/gal; or Metribuzin 75; TriCor DF or others, 75%) + EPTC (Eptam) or S-metolachlor (Dual Magnum) or pendimethalin (Prowl 3.3EC or Prowl H2O)

Rate 1 to 1.5 oz/a rimsulfuron + 0.5 to 1 pint/a metribuzin 4 or 0.33 to 0.67 lb/a metribuzin 75%DF + 3.5 to 4.5 pints/a Eptam or 1.5 to 2 pints/a Dual Magnum or 1.2 to 2.4 pints/a of Prowl 3.3EC or 1.5 to 3 pints/a Prowl H2O

Time Apply after planting or after hilling or dragoff, but before potatoes or weeds emerge. The rimsulfuron + metribuzin + Eptam mixture also may be applied postemergence to small weeds (less than 1 inch high or across) before potatoes are 4 to 6 inches tall.

Remarks Three-way mixtures of rimsulfuron + metribuzin + Eptam or Dual Magnum or Prowl 3.3EC or Prowl H2O control hairy nightshade in heavily infested fields better than rimsulfuron + metribuzin or rimsulfuron alone. Whether to use Eptam, Dual Magnum, Prowl 3.3 EC or Prowl H2O in the three-way mix depends on which other weeds infest the field. See herbicide efficacy tables for common weed species at the end of this section. See the previous entries in this section for application and incorporation methods, remarks, cautions, and re-cropping and rotational cropping restriction information for these herbicides.

Caution Read and follow all label recommendations for companion herbicides. If recommendations conflict with rimsulfuron label, do not use in a tank-mix with rimsulfuron. Use lower rates on coarse, sandy soils and the higher rate on fine-texture soils. If using the rimsulfuron + metribuzin + Eptam mix postemergence, use nonionic surfactant at 0.125% v/v (1 pint/100 gal spray solution). Do not use on seed potatoes unless a supplemental label permits. See previous entries in this section for potato variety sensitivity to metribuzin. In general, do not apply this tank-mixture postemergence to early-maturing, smooth-skinned, white-skinned, or red-skinned varieties of potato.

Site of action (rimsulfuron) Group 2: acetolactate synthase (ALS) inhibitor; (metribuzin) Group 5: photosystem II inhibitor; (EPTC) Group 8: lipid synthesis inhibitor but not an ACCase inhibitor; (S-metolachlor) Group 15: inhibits very long chain fatty acid synthesis; (pendimethalin) Group 3: microtubule assembly inhibitor

Chemical family (rimsulfuron) sulfonylurea; (metribuzin) triazinone; (EPTC) thiocarbamate; (S-metolachlor) chloroacetamide; (pendimethalin) dinitroaniline

rimsulfuron (Matrix SG; Matrix FNV; Solida; or others, 25%) + S-metolachlor (Dual Magnum)

Rate 1 to 1.5 oz/a Matrix + 1.5 to 2 pints/a Dual Magnum

Time Apply after planting as a delayed preemergence treatment (after dragoff or hilling but before crop and weeds emerge).

Remarks Tank-mix controls small-seed grasses, hairy and cutleaf nightshade, and common lambsquarters better than rimsulfuron alone. A three-way mixture of rimsulfuron + Dual Magnum + Eptam or Prowl 3.3EC or Prowl H2O may be used after planting but before potatoes and weeds emerge. See previous entries in this section for application and incorporation methods, remarks, cautions, and re-cropping and rotational cropping restriction information.

Caution Do not use on seed potatoes unless permitted by a supplemental label.

Site of action (rimsulfuron) Group 2: acetolactate synthase (ALS) inhibitor; (S-metolachlor) Group 15: inhibits very long chain fatty acid synthesis

Chemical family (rimsulfuron) Sulfonylurea; (S-metolachlor) Chloroacetamide

rimsulfuron (Matrix SG; Matrix FNV; Solida; or others, 25%) + pendimethalin (Prowl 3.3EC or Prowl H2O)

Rate 1 to 1.5 oz/a rimsulfuron + 1.2 to 2.4 pints/a of Prowl 3.3EC or 1.5 to 3 pints/a Prowl H2O

Time Apply after planting or after dragoff but before potatoes and weeds emerge.

Remarks Tank-mix controls kochia (including rimsulfuron-resistant kochia), common lambsquarters, Russian thistle, and crabgrass better than rimsulfuron alone. Rimsulfuron + Prowl 3.3 EC or Prowl H2O controls hairy nightshade but does not control cutleaf nightshade. A mixture of rimsulfuron + Prowl 3.3 EC or Prowl H2O + Eptam or Dual Magnum may be used after planting but before potatoes and weeds emerge. Either three-way mixture controls hairy and cutleaf nightshade more effectively than rimsulfuron + Prowl 3.3 EC or Prowl H2O. See previous entries in this section for application and incorporation methods, remarks, cautions, and re-cropping and rotational cropping restriction information for these herbicides.

Caution Do not use on seed potatoes unless permitted by a supplemental label.

Site of action (rimsulfuron) Group 2: acetolactate synthase (ALS) inhibitor; (pendimethalin) Group 3: microtubule assembly inhibitor

Chemical family (rimsulfuron) Sulfonylurea; (pendimethalin) Dinitroaniline

sethoxydim (Poast or Poast Plus) + metribuzin (Metribuzin 4L or others, 4 lb ai/gal; or Metribuzin 75; TriCor DF or others, 75%)

Rate 1 to 2.5 pints/a Poast; or 1.5 to 2.25 pints/a Poast Plus + 0.75 to 0.94 pint/a metribuzin 4 or 0.5 to 0.63 lb/a metribuzin 75%DF

Time Apply postemergence to actively growing weeds at growth stage recommended on product labels.

Remarks Always add a nonphytotoxic oil concentrate at 2 pints/a to the spray tank. Do not apply if target grasses include quackgrass, rhizome Johnsongrass, volunteer corn, wirestem muhly, shattercane, red rice, itchgrass, or bermudagrass. Do not cultivate within 5 days before or 7 days after applying the tank-mix. See the previous entries in this section for application and incorporation methods, remarks, cautions, and re-cropping and rotational cropping restriction information for these herbicides.

Caution Do not apply this tank-mix with other herbicides. Do not apply this tank-mix if grasses to be controlled include rhizome Johnsongrass, quackgrass, Bermudagrass, wirestem muhly, volunteer corn or cereal, shattercane, red rice, or itchgrass. Oil concentrate, required for sethoxydim efficacy, may reduce potato tolerance to metribuzin. Do not add nitrogen to this tank-mix. Do not apply to crop under stress or injured by previous herbicide treatment. Apply only if weather has been sunny at least 3 successive days before application. See previous entries in this section for potato variety sensitivity to metribuzin. In general, do not apply this tank-mixture postemergence to early-maturing, smooth-skinned, white-skinned, or red-skinned varieties of potato. Do not apply through any type of irrigation system.

Site of action (sethoxydim) Group 1: acetyl CoA carboxylase (ACCase) inhibitor; (metribuzin) Group 5: photosystem II inhibitor

Chemical family (sethoxydim) Cyclohexanedione; (metribuzin) Triazinone

S-metolachlor (Dual Magnum) + metribuzin (Metribuzin 4L or others, 4 lb ai/gal; or Metribuzin 75; TriCor DF or others, 75%)

Rate 1 to 2 pints/a Dual Magnum + 0.75 to 2 pints/a metribuzin 4 or 0.5 to 0.67 lb/a 75%DF

Time Apply as a tank-mixture any time after planting until immediately after last hilling but before potatoes emerge. This combination may be applied as a tank-mix or sequentially.

Remarks Use lower rates on coarse soils or soils low in organic matter; use higher rate on fine-texture or high-organic-matter soils. When applied through a center pivot system, apply proper rates in 0.5 to 1 inch of water (depending on soil type). See the previous entries in this section for application and incorporation methods, remarks, cautions, and re-cropping and rotational cropping restriction information for these herbicides.

Caution Do not mechanically incorporate this tank-mix into soil. Mechanically cultivating metribuzin after treatment decreases weed control and may injure potatoes.

Site of action (S-metolachlor) Group 15: inhibits very long chain fatty acid synthesis; (metribuzin) Group 5: photosystem II inhibitor

Chemical family (S-metolachlor) Chloroacetamide; (metribuzin) Triazinone

S-metolachlor (Dual Magnum) + pendimethalin (Prowl 3.3EC or Prowl H2O)

Rate 1 to 1.67 pints/a Dual Magnum + 1.2 to 2.4 pints/a. Prowl 3.3EC or 1.5 to 3 pints/a Prowl H2O

Time Apply after planting but before potatoes and weeds emerge.

Remarks Use lower rates on coarse soils and higher rates on finer, heavier soils. The tank-mixture will not control emerged weeds. See the previous entries in this section for application and incorporation methods, remarks, cautions, and re-cropping and rotational cropping restriction information for these herbicides.

Caution Follow the Dual Magnum and Prowl labels' most restrictive directions, timing, limitations, precautions, and restrictions on use in potatoes.

Site of action (S-metolachlor) Group 15: inhibits very long chain fatty acid synthesis; (pendimethalin) Group 3: microtubule assembly inhibitor

Chemical family (S-metolachlor) Chloroacetamide; (pendimethalin) Dinitroaniline

S-metolachlor (Magnum) + pendimethalin (3.3EC or Prowl H2O) + EPTC (Eptam)

Rate 1 to 1.67 pints/a Dual Magnum + 1.2 to 2.4 pints/a Prowl 3.3EC or 1.5 to 3 pints/a Prowl H2O + 3.5 to 7 pints/a Eptam

Time Apply after planting but before potatoes and weeds emerge.

Remarks Use lower rates on coarse soils and higher rates on finer, heavier soils. The tank-mixture will not control emerged weeds.

Caution Follow Dual Magnum, Prowl 3.3 EC or Prowl H2O, and Eptam labels' most restrictive directions, timing, limitations, precautions, and restrictions on use in potatoes. See the previous entries in this section for application and incorporation methods, remarks, cautions, and re-cropping and rotational cropping restriction information for these herbicides.

Site of action (S-metolachlor) Group 15: inhibits very long chain fatty acid synthesis; (pendimethalin) Group 3: microtubule assembly inhibitor; (EPTC) Group 8: lipid synthesis inhibitor but not an ACCase inhibitor

Chemical family (S-metolachlor) Chloroacetamide; (pendimethalin) Dinitroaniline; (EPTC) Thiocarbamate

trifluralin (HFP; or others) + EPTC (Eptam)

Rate 1 to 1.5 pints/a Treflan HFP + 3.5 pints/a Eptam

Time Apply and immediately incorporate after planting but before potatoes and weeds emerge. Or, in areas where potatoes normally are dragged off, apply and incorporate up to or right after dragoff.

Remarks Incorporate with equipment that will not damage potato seed pieces or elongating sprouts. Set incorporation equipment so a layer of treated soil uniformly covers bed and furrow. See previous entries in this section for application and incorporation methods, remarks, cautions, and re-cropping and rotational cropping restriction information for these herbicides.

Caution To help prevent crop injury, carefully follow labels before applying. Potatoes may be injured severely if these herbicides are applied after potatoes emerge if subsequent mechanical incorporation covers potatoes with treated soil.

Site of action (trifluralin) Group 3: microtubule assembly inhibitor; (EPTC) Group 8: lipid synthesis inhibitor but not an ACCase inhibitor

Chemical family (trifluralin) Dinitroaniline; (EPTC) Thiocarbamate