Common corn and soybean herbicides, estimated half-lives, cash crop restrictions and their potential to injure fall cover crops.

Please note that the listing of any particular herbicide in the listing below does not constitute an endoresement of any kind for any product.  Products listed are believed to be common products and are listed for illustrative purposes with respect to their effects on cover crop plantings.  Information is based on Eastern U.S. information and may not be applicable to other locations.  Please be sure to discuss your options with your Bio Till Cover Crop Dealer or Bio Till Cover Crop Expert prior to any planting or business decision.

Corn

Active ingredient: 2,4-D

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
1 – 2 pt7Plant anything 30 days after applicationAll grassesWait 30 days before planting sensitive broadleavesAmine formulations more water soluble and can leach into seed zone

Active ingredient: nicosulfuron / nicosulfuron + rimsulfuron

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
0.66 oz / 0.75 oz21Sensitive crops have 10 – 18 month restrictionFall cereal grains, ryegrassSmall seeded legumes, mustards, sorghumMore persistent in high pH soils (>7)

Active ingredient: atrazine

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
1 – 2 qt60Can plant corn, sorghum, and soybean the following year (some products allow others)Sorghum speciesCereals, ryegrass, legumes, and mustardsMore persistent in high pH soils (>7). Rates <1 lb/acre can allow more flexibility

Active ingredient: isoxaflutole

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
3 fl. oz

6 fl. oz

50 – 120Small seeded leg umes and vegetables have a 10 to 18 month restrictionFall cereal grainsCereals, Ryegrass, legumes, and mustards15 inches of cumulative precipitation required from application to planting rotation crops except soybean, barely, weat, sorghum, and sunflower

Active ingredient: mesotrione

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
3 – 6 fl. oz5 – 3210 to 18 months for legumes and vegetablesAll grassesSmall seeded legumes, mustardsSequential applications (PRE fb POST) increase the potential for injury

Active ingredient: dicamba

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
16 to 24 fl. oz5 – 1415 days per 8 fl. oz/acre for small grainsAll cropsOnly at high rates or less than 120 days after applicationAnything can be planted after 120 days with 24 fl. oz/acre or less

Active ingredient: metolachlor

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
1.67 pt15 – 50Labeled for use on many cropsAlmost anythingAnnual ryegrass or other small seeded grassesHigher rates and later applications more of a potential problem

Active ingredient: tembotrione + thiencarbazone

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
3 fl. oz15Four mo. for wheat, 10 mo. for barley, sorghum, oats and alfalfaWheat, triticale, ryeSmall seeded legumes, mustards, sorghum15 inches of cumulative precipitation required from application to planting rotation crops except wheat

Active ingredient: isoxaflutole + thiencarbazone

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
5.6 fl. oz50 – 120Four mo. for wheat, 9 mo. for barley and 17 mo. for alfalfa, oats, soghum, and canolaWheat, triticale, ryeSmall seeded legumes, mustards, sorghum15 to 30 inches of cumulative precipitation from application to planting for sensitive crops

Active ingredient: acetochlor

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
2 pt10 – 20Four mo. for wheat and 9 mo. for alfalfa and cloversMost crops should be fineFood or feed residues rather than crop injury may be a concernNonfood / feed winter cover crops are allowed after corn harvest

Active ingredient: topromesone

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
0.75 fl. oz14Alfalfa, canola, soybean and sunflower have a 9 mo. restrictionWheat, barley, oats, and rye are allowed after 3 mo. Ryegrass should also be OKAlthough many broadleaves are restricted, Impact does not have much soil activity

Active ingredient: tembotrione

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
3 fl. oz14Four mo. for cereal grains, 10 mo. for sorghum, canola, and alfalfaCereal grains after 4 mo.Unknown – Small seeded legumes, mustards could be a problemOther crops may be seeded after a successful field bioassay.

Active ingredient: prosulfuron

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
1 oz9 – 152Cash crop restrictions ranged from 10 mo. for soybean and tobacco to 22 mo. for alfalfa and canolaCereal grains and sorghum are labeled, other grassesSmall seeded legumes, mustardsMore persistent in high pH soils (>7)

Active ingredient: halosulfuron

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
2 / 3 oz9 – 27Nine mo. for alfalfa, clovers, soybean and 15 mo. for canolaCereal grains and sorghum after 2 mo. and other grassesSmall seeded legumes, mustardsHalosulfuron also an ingredient in Yukon

Active ingredient: rimsulfuron

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
2 oz2 – 4Winter cereals have a 3 mo. restriction and many crops are restricted for 10 mo.Based on the short half-life, most fall cover crops should be OK in PANoneMore persistent in drought conditions

Active ingredient: simazine

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
1 – 2 qt60Can plant corn, sorghum, and soybean the following year (some products allow others)Sorghum speciesCereals, Ryegrass, legumes, and mustardsSoil pH > 7

Active ingredient: clopyralid

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
5 oz40Recrop intervals 10.5 to 18 mo. for legumesAll grassesSmall seeded legumes

Soybean

Active ingredient: quizalofop

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
8 oz60Most broadleaves OKMost broadleavesAll grasses if less than 120 days or at high ratesPlant anything after 120 days

Active ingredient: sulfentrazone

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
4 oz32 – 30212 to 24 months for legumes and some vegetablesCereals and ryegrassSmall seeded legumes, mustards, sorghumLabeled on tobacco, sunflowers, transplanted tomato

Active ingredient: chlorimuron

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
0.5 – 2 oz4012 to 30 months for small seeded legumesCereals and ryegrassSmall seeded legumes, mustards, sorghumMore persistent in high pH soils (>7) and with higher soil applied rates

Active ingredient: cloransulam

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
0.3 to 0.6 oz8 – 33Four months to wheat, 9 mo. to alfalfa, corn, sorghum and oats, 12 mo. for barley, and 18 mo. for tobaccoWheat, triticale, ryeSmall seeded legumes, mustards, sorghumThe restriction for transplanted tobacco is 10 mo. for 0.3 oz/acre. Sugarbeet and sunflower have a 30 month restriction.

Active ingredient: imazethapyr

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
4 fl. oz60 – 90Recrop restrictions range from 4 to 18 mo.Wheat, triticale, rye, alfalfa, cloverOats, sorghum, mustardsAny crop can be planted 40 months after Pursuit application

Active ingredient: imazamox

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
5 fl. oz20 – 30Recrop intervals range from 3 to 18 mo.Wheat, triticale, rye, alfalfa, cloversSlight risk for mustardsMost cash crops allowed 9 mo. following application

Active ingredient: fomesafen

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
1.5 pt100Recrop intervals range from 4 to 18 monthsCereal grainsSmall seeded legumes, mustards, sorghumSince fomesafen is often applied postemergence, soil activity can surprise users

Active ingredient: imazaquin

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
0.66 pt60 – 90Recrop intervals range from 11 to 18 monthsCereal grainsSmall seeded legumes, mustardsCarryover much more of a risk with drought

Active ingredient: clethodim

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
10 oz3Most broadleaves OKAll broadleavesNone assuming at least 30 daysPlant anything after 30 days

Active ingredient: flumioxazin

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
2.5 oz12 – 20Recrop restrictions up to 10 mo. for no-till alfalfa, clover and 12 mo. for no-till canolaAll grassesSmall seeded legumes and mustardsBased on the half-life, all nonfood / feed winter cover crops should be OK

Soybean and Corn

Active ingredient: glyphosate

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
0.75 to 1.25 lb47No restrictions preemergenceAllNoneGlyphosate does not have soil activity at normal use rates

Active ingredient: paraquat

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
2 pt1000No restrictions preemergenceAllNoneParaquat does not have soil activity at normal use rates

Active ingredient: thifensulfuron

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
1/8 oz12Any crop can be planted 45 days after applicationNo restrictions for wheat, barley, and oatsNone with 45 day waiting intervalHarmony Extra also contains tribenuron

Active ingredient: glufosinate

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
22 – 36 fl. oz7No restrictions for canola, corn, and soybean. Small grains have a 70 day restriction.AllFood or feed residues rather than crop injury may be a concernGlufosinate does not have soil activity at normal use rates

Active ingredient: metribuzin

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
0.33 lb14 – 60Recrop restrictions range from 4 to 12 mo.Cereal grains and ryegrassSlight risk for small seeded legumes and mustardsNonfood / feed winter cover crops allowed

Active ingredient: dimethenamid

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
16 fl. oz20Four mo. for cereal grains and anything the following springMost crops should be fineFood or feed residues rather than crop injury may be a concernNonfood / feed winter cover crops should be OK after corn harvest

Active ingredient: pendamethalin

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
3 pt44Wheat and barley after 4 mo. Other rotational crops the following year.Cereal grainsSmall seeded legumes and annual ryegrassNonfood / feed winter cover crops should be OK

Active ingredient: flumetsulam

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
1 oz14 – 120Cash crop restrictions from 4 mo. for alfalfa and cereals to 26 mo. for canolaCereal grainsSmall seeded legumes, mustards, and annual ryegrassCover crops and forage grasses are restricted for 9 mo.

Active ingredient: saflufenacil

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
3 fl. oz7 – 35Any crop can be planted 4 mo. after applicationAllNoneThis product has been reported more persistent in western Canada

Active ingredient: pyroxasulfone

Normal Rate/acreHalf life (days)Cash crop restrictionsOK (Fall Cover Crops)Concern (Fall Cover Crops)Other
0.133204 mo. for wheat, 11 mo. for other small grains, and 10 mo. for alfalfaMost crops should be fineFood or feed residues rather than crop injury may be a concernNonfood / feed winter cover crops should be OK after corn harvest

Information on this page and in the above tables can originally be found at:  Herbicides Persistence And Rotation To Cover Crops. (n.d.). Retrieved from http://blog.uvm.edu/cvcrops/files/2012/09/Cover_crop_and_herbicides.pdf