Table 1. Common corn herbicides, estimated half-lives, and their potential to injure fall-seeded cover crops. dicamba All crops

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1 Table 1. Common corn herbicides, estimated half-lives, and their potential to injure fall-seeded cover crops. Herbicide Common name Group # Half life (days)* 2,4-D 2,4-D 4 7 All Accent 75DF nicosulfuron 2 21 Fall cereal grains, ryegrass Atrazine 4L atrazine 5 60 Sorghum species Banvel II, Distinct Broadstrike RC Callisto (includes Lumax, Lexar, Halex GT) dicamba All crops flumetsulam mesotrione All Wait 30 days before planting sensitive broadleaves, sorghum Cereals, ryegrass, legumes, and Only at high rates or less than 120 days after application Hairy vetch, tillage radish Amine formulations more water soluble and can leach into seed zone high ph soils (>7) high ph soils (> 7). Rates < 1 lb/acre can allow more flexibility Anything can be planted after 120 days with 24 fl. oz/acre or less Sequential applications (PRE fb POST) increase the potential for injury Converge XT isoxaflutole + atrazine 27, Sorghum species Cereals, Ryegrass, legumes, and 15 inches of cumulative precipitation required from application to

2 Herbicide Common name Group # Half life (days)* Dual II Mag 7.62E/Cinch Fierce s-metolachlor Almost anything pyroxasulfone + flumioxazin 15, 14 Impact/Armezon tompramezone Lontrel (Hornet, Surestart) Peak 75WG (Spirit) All Wheat, barley, oats, and rye are allowed after 3 mo. Ryegrass should also be OK clopyralid 4 40 All prosulfuron Permit/Sandea 75DF halosulfuron Cereal grains and sorghum are labeled, other Cereal grains and sorghum after 2 mo. and other Annual ryegrass or other small seeded legumes and Although many broadleaves are restricted, Impact does not have much soil activity including hairy vetch and crimson clover planting rotation crops except soybean, barley, wheat, sorghum, and sunflower Higher rates and later applications more of a potential problem Based on the halflife, all nonfood/feed winter cover crops should be OK clovers may be injured high ph soils Halosulfuron also an ingredient in Yukon

3 Herbicide Common name Group # Half life (days)* Prism rimsulfuron None Simazine (Princep 9-T) simazine 5 60 Sorghum species Cereals, ryegrass, legumes, and drought conditions Soil ph > 7

4 Table 2. Common soybean herbicides, their half lives, and potential to injure fall-seeded cover crops. Herbicide Common name Group # Half Life (days)* Cover Crops Cover Crops (Concern For) Assure II quizalofop 1 60 Canopy Pro chlorimuron + metribuzin 2, 5 40 Command clomazone FirstRate cloransulam Guardian chlorimuron 2 40 Pinnacle thifensulfuron 2 12 Pursuit imazethapyr Reflex fomesafen OK to plant most broadleaves Oilseed radish Wheat, triticale, rye Cereals and ryegrass No restriction for wheat, barley and oats Wheat, triticale, rye, alfalfa, clover Cereal grains Concern for all if less than 120 days or at high rates Winter rye, winter wheat and somewhat on oats, small seeded legumes,, Winter rye, winter wheat and somewhat on oats legumes,, legumes,, None with 45 day waiting interval Oats, sorghum,, buckwheat legumes,, tillage radish, Plant anything after 120 days high ph soils (> 7) and with higher soil applied rates high ph soils (> 7) and with higher soil applied rates Any crop can be planted 40 months after Pursuit application Since fomesafen is often applied postemergence,

5 Select (Arrow) clethodim 1 3 Sencor 75 DF metribuzin Treflan trifluralin 3 45 Valtera flumioxazin All broadleaves Cereal grains and ryegrass Annual ryegrass, oats All sorghum None assuming at least 30 days Slight risk for small seeded legumes and buckwheat legumes and Herbicide half-life estimates derived from the WSSA Herbicide Handbook, 2007 or other scientific literature. soil activity can surprise users Plant anything after 30 days Nonfood/feed winter cover crops allowed Based on the halflife, all nonfood/feed winter cover crops should be OK