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/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
1 – 2 pt 7 Plant anything 30 days after application All grasses Wait 30 days before planting sensitive broadleaves Amine formulations more water soluble and can leach into seed zone

Active ingredient: nicosulfuron / nicosulfuron + rimsulfuron

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
0.66 oz / 0.75 oz 21 Sensitive crops have 10 – 18 month restriction Fall cereal grains, ryegrass Small seeded legumes, mustards, sorghum More persistent in high pH soils (>7)

Active ingredient: atrazine

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
1 – 2 qt 60 Can plant corn, sorghum, and soybean the following year (some products allow others) Sorghum species Cereals, ryegrass, legumes, and mustards More persistent in high pH soils (>7). Rates <1 lb/acre can allow more flexibility

Active ingredient: isoxaflutole

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
3 fl. oz

6 fl. oz

50 – 120 Small seeded leg umes and vegetables have a 10 to 18 month restriction Fall cereal grains Cereals, Ryegrass, legumes, and mustards 15 inches of cumulative precipitation required from application to planting rotation crops except soybean, barely, weat, sorghum, and sunflower

Active ingredient: mesotrione

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
3 – 6 fl. oz 5 – 32 10 to 18 months for legumes and vegetables All grasses Small seeded legumes, mustards Sequential applications (PRE fb POST) increase the potential for injury

Active ingredient: dicamba

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
16 to 24 fl. oz 5 – 14 15 days per 8 fl. oz/acre for small grains All crops Only at high rates or less than 120 days after application Anything can be planted after 120 days with 24 fl. oz/acre or less

Active ingredient: metolachlor

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
1.67 pt 15 – 50 Labeled for use on many crops Almost anything Annual ryegrass or other small seeded grasses Higher rates and later applications more of a potential problem

Active ingredient: tembotrione + thiencarbazone

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
3 fl. oz 15 Four mo. for wheat, 10 mo. for barley, sorghum, oats and alfalfa Wheat, triticale, rye Small seeded legumes, mustards, sorghum 15 inches of cumulative precipitation required from application to planting rotation crops except wheat

Active ingredient: isoxaflutole + thiencarbazone

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
5.6 fl. oz 50 – 120 Four mo. for wheat, 9 mo. for barley and 17 mo. for alfalfa, oats, soghum, and canola Wheat, triticale, rye Small seeded legumes, mustards, sorghum 15 to 30 inches of cumulative precipitation from application to planting for sensitive crops

Active ingredient: acetochlor

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
2 pt 10 – 20 Four mo. for wheat and 9 mo. for alfalfa and clovers Most crops should be fine Food or feed residues rather than crop injury may be a concern Nonfood / feed winter cover crops are allowed after corn harvest

Active ingredient: topromesone

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
0.75 fl. oz 14 Alfalfa, canola, soybean and sunflower have a 9 mo. restriction Wheat, barley, oats, and rye are allowed after 3 mo. Ryegrass should also be OK Although many broadleaves are restricted, Impact does not have much soil activity

Active ingredient: tembotrione

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
3 fl. oz 14 Four mo. for cereal grains, 10 mo. for sorghum, canola, and alfalfa Cereal grains after 4 mo. Unknown – Small seeded legumes, mustards could be a problem Other crops may be seeded after a successful field bioassay.

Active ingredient: prosulfuron

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
1 oz 9 – 152 Cash crop restrictions ranged from 10 mo. for soybean and tobacco to 22 mo. for alfalfa and canola Cereal grains and sorghum are labeled, other grasses Small seeded legumes, mustards More persistent in high pH soils (>7)

Active ingredient: halosulfuron

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
2 / 3 oz 9 – 27 Nine mo. for alfalfa, clovers, soybean and 15 mo. for canola Cereal grains and sorghum after 2 mo. and other grasses Small seeded legumes, mustards Halosulfuron also an ingredient in Yukon

Active ingredient: rimsulfuron

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
2 oz 2 – 4 Winter 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 PA None More persistent in drought conditions

Active ingredient: simazine

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
1 – 2 qt 60 Can plant corn, sorghum, and soybean the following year (some products allow others) Sorghum species Cereals, Ryegrass, legumes, and mustards Soil pH > 7

Active ingredient: clopyralid

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
5 oz 40 Recrop intervals 10.5 to 18 mo. for legumes All grasses Small seeded legumes

Soybean

Active ingredient: quizalofop

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
8 oz 60 Most broadleaves OK Most broadleaves All grasses if less than 120 days or at high rates Plant anything after 120 days

Active ingredient: sulfentrazone

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
4 oz 32 – 302 12 to 24 months for legumes and some vegetables Cereals and ryegrass Small seeded legumes, mustards, sorghum Labeled on tobacco, sunflowers, transplanted tomato

Active ingredient: chlorimuron

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
0.5 – 2 oz 40 12 to 30 months for small seeded legumes Cereals and ryegrass Small seeded legumes, mustards, sorghum More persistent in high pH soils (>7) and with higher soil applied rates

Active ingredient: cloransulam

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
0.3 to 0.6 oz 8 – 33 Four months to wheat, 9 mo. to alfalfa, corn, sorghum and oats, 12 mo. for barley, and 18 mo. for tobacco Wheat, triticale, rye Small seeded legumes, mustards, sorghum The 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/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
4 fl. oz 60 – 90 Recrop restrictions range from 4 to 18 mo. Wheat, triticale, rye, alfalfa, clover Oats, sorghum, mustards Any crop can be planted 40 months after Pursuit application

Active ingredient: imazamox

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
5 fl. oz 20 – 30 Recrop intervals range from 3 to 18 mo. Wheat, triticale, rye, alfalfa, clovers Slight risk for mustards Most cash crops allowed 9 mo. following application

Active ingredient: fomesafen

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
1.5 pt 100 Recrop intervals range from 4 to 18 months Cereal grains Small seeded legumes, mustards, sorghum Since fomesafen is often applied postemergence, soil activity can surprise users

Active ingredient: imazaquin

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
0.66 pt 60 – 90 Recrop intervals range from 11 to 18 months Cereal grains Small seeded legumes, mustards Carryover much more of a risk with drought

Active ingredient: clethodim

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
10 oz 3 Most broadleaves OK All broadleaves None assuming at least 30 days Plant anything after 30 days

Active ingredient: flumioxazin

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
2.5 oz 12 – 20 Recrop restrictions up to 10 mo. for no-till alfalfa, clover and 12 mo. for no-till canola All grasses Small seeded legumes and mustards Based on the half-life, all nonfood / feed winter cover crops should be OK

Soybean and Corn

Active ingredient: glyphosate

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
0.75 to 1.25 lb 47 No restrictions preemergence All None Glyphosate does not have soil activity at normal use rates

Active ingredient: paraquat

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
2 pt 1000 No restrictions preemergence All None Paraquat does not have soil activity at normal use rates

Active ingredient: thifensulfuron

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
1/8 oz 12 Any crop can be planted 45 days after application No restrictions for wheat, barley, and oats None with 45 day waiting interval Harmony Extra also contains tribenuron

Active ingredient: glufosinate

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
22 – 36 fl. oz 7 No restrictions for canola, corn, and soybean. Small grains have a 70 day restriction. All Food or feed residues rather than crop injury may be a concern Glufosinate does not have soil activity at normal use rates

Active ingredient: metribuzin

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
0.33 lb 14 – 60 Recrop restrictions range from 4 to 12 mo. Cereal grains and ryegrass Slight risk for small seeded legumes and mustards Nonfood / feed winter cover crops allowed

Active ingredient: dimethenamid

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
16 fl. oz 20 Four mo. for cereal grains and anything the following spring Most crops should be fine Food or feed residues rather than crop injury may be a concern Nonfood / feed winter cover crops should be OK after corn harvest

Active ingredient: pendamethalin

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
3 pt 44 Wheat and barley after 4 mo. Other rotational crops the following year. Cereal grains Small seeded legumes and annual ryegrass Nonfood / feed winter cover crops should be OK

Active ingredient: flumetsulam

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
1 oz 14 – 120 Cash crop restrictions from 4 mo. for alfalfa and cereals to 26 mo. for canola Cereal grains Small seeded legumes, mustards, and annual ryegrass Cover crops and forage grasses are restricted for 9 mo.

Active ingredient: saflufenacil

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
3 fl. oz 7 – 35 Any crop can be planted 4 mo. after application All None This product has been reported more persistent in western Canada

Active ingredient: pyroxasulfone

Normal Rate/acre Half life (days) Cash crop restrictions OK (Fall Cover Crops) Concern (Fall Cover Crops) Other
0.133 20 4 mo. for wheat, 11 mo. for other small grains, and 10 mo. for alfalfa Most crops should be fine Food or feed residues rather than crop injury may be a concern Nonfood / 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