Cover Crops and Conservation Tillage for Soil Erosion Control on Cropland

Table of Contents

Table 5. Herbicide effectiveness on common weeds in corn planted into established birdsfoot trefoil/crownvetch cover.¹
Cover Crops Treatment no. from Table 4
10² 11 12 13, 14 15 16 17 18 19 20
Crownvetch 9+ 9 6 8 5 8+ 5 N 5 6
Birdsfoot trefoil 9 5 6 8 5 8+ 6 6 5 6
Summer annuals
Barnyardgrass 10 10 8 9+ 8+ N 9 8+ 8+ N
Black medic 9 10 ? 10 9 9 ? ? ? ?
Buckwheat, wild 10 9 9 10 9 10 ? ? ? ?
Burcucumber 9 9 6 5 ? 6 7 ? 6 6
Chamomile, mayweed 9 10 ? 9+ 5 8 ? ? ? ?
Cocklebur, common 10 10 9 8+ 9 9+ 10 9+ 7 9
Crabgrass, large or smooth 9 10 8 9+ 8 N 8 9 7+ N
Foxtail, giant 9 10 9 9 9 N 9 8 9 N
Foxtail, green 10 10 9 9+ 9 N 9 8+ 9 N
Foxtail, yellow 10 10 8 9+ 7 N 9 8+ 9 N
Galinsoga, hairy 10 10 10 10 9 10 9 ? ? ?
Goosegrass 9 10 9 9+ 7 N 9 9 ? N
Jimsonweed 10 10 8 9 9 9 8 6 7 N
Johnsongrass (seedling) - 10 9 7 8 N 7 7+ 9+ N
Ladysthumb 10 10 8+ 9 9 10 9 ? 8 8
Lambsquarters, common 10 10 8 9 9 9 10 9 7 N
Lambsquarters, TR 8 10 8 7 9 9 10 9 7 N
Morningglory, ivyleaf 10 10 8 10 5? 10 10 10 9 6
Morningglory, tall 10 10 8 10 5? 10 10 10 9 6
Mustard, wild 10 10 10 10 9 10 9+ ? 9 ?
Nightshade, eastern black 10 10 8+ 10 9 10 9 N ? 6
Panicum, fall 9 10 8 9 7 N 9 5 9 N
Pigweed, redroot 10 10 10 9 9+ 9 10 9+ 9 9
Pigweed, smooth TR 10 10 10 8+ 9+ 9 10 9 9 9
Purslane, common 10 10 10 10 9 10 9 ? ? ?
Radish, wild 9 10 ? 9+ 8 9 8 ? ? ?
Ragweed, common 10 10 9 10 9 9 9 5 5 9
Ragweed, giant 9 10 8+ 9 7 9 ? N 6 8
Shattercane 9 10 9 6 8+ N 7 9+ 9+ N
Smartweed, Pennsylvania 10 10 8+ 9 9 10 9 8 8 8
Velvetleaf 10 10 8+ 8+ 9 8 9 8+ 7 9
Witchgrass 9 10 9 9 8 N 9 9 9 N
Winter annuals
Brome, downy 9 10 ? 8 5 N 6 ? ? N
Brome, Japanese 9 10 ? 8 5 N 6 ? ? N
Cheat 9 10 ? 8 5 N 6 ? ? ?
Chickweed, common 10 10 ? 10 9 7 9 ? ? ?
Deadnettle, purple 9 10 ? 10 9 8 ? ? ? ?
Fleabane, rough 8 10 ? 10 ? 9 ? ? ? ?
Henbit 9 10 ? 10 9 8 9 ? ? ?
Horseweed 8 10 ? 10 N 9 5 ? ? ?
Lettuce, prickly 9 10 ? 10 ? 9 ? ? ? ?
Mustard, birdsrape ? 10 ? 9 8 9 8 ? ? ?
Pennycress, field 9 10 ? 10 9 10 9 ? ? ?
Pepperweed, field 9 10 ? 10 9 10 9 ? ? ?
Shepherd’s purse 9+ 10 ? 10 9 10 9 ? ? ?
Woodsorrel, yellow 10 10 ? 10 ? 8 9 ? ? ?
Biennials
Burdock, common 9* 8 ? 5 N 8 N N ? ?
Carrot, wild 9* 9 ? 9 N 9 N N ? ?
Fleabane, rough 9* 9 ? 9 ? 9 ? N ? ?
Parsnip, wild 9* 9 ? 7 N 8 N N ? ?
Thistle, plumeless 9* 9 ? 7 N 8 N N ? ?
Perennials
Bedstraw, smooth 9* 9 ? ? N 5 N N ? ?
Bindweed, field 9* 8+ 5 N N 7 N N ? ?
Bindweed, hedge 9* 8+ 5 N N 7 N N ? ?
Blackberry 8* 8 ? N N 5 N N 6 ?
Chamomile, corn 9* 9 ? 9+ N 8 N N ? ?
Chickweed, mouseear 9* 9 ? 9+ 9 7 ? N ? ?
Cinquefoil, sulfur 9* 9 ? 9 N 8 N N ? ?
Cockle, white 9* 8+ ? 5 N 7 N N N ?
Dandelion 9* 6 5 5 N 7 N N 8 ?
Dewberry, northern 9* 7 ? N N 5 N N 9 ?
Dock, broadleaf and curly 9* 8 ? 5 N 9 N N ? ?
Dogbane, hemp 9* 7 5 N N 7+ N N 7+ ?
Garlic, wild 8* 7 ? 7 N 8 N N ? ?
Goldenrod 9* 8 ? N N 8 N N ? ?
Groundcherry 9* 8 ? 5 N 8 N N ? ?
Horsenettle 9* 7 ? N N 6 N N ? ?
Johnsongrass (established) 9* 9 7 N 6 N N N 8+ N
Milkweed, common 9* 5 5 N N 6 N N ? ?
Nutsedge, yellow 9* 9 7 9 7 N 7 N 6 9+
Plantains 9* 8 ? 7 N 8 5 N ? ?
Poison ivy 9* 7 ? N N 5 N N ? ?
Pokeweed, common 8* 8 5 N N 5 N N ? 8
Quackgrass 9* 8 6 7 N N 5 N 9 N
Rocket, yellow 9* 9 ? 9 9 9 9 N ? ?
Sorrel, red 9* 8 ? 7 N 9 N N ? ?
Thistle, Canada 9* 7 5 5 N 8 N N 6 ?
Wirestem muhly 9* 9 N 7 N N N N 6 N
¹ 10 = 95–100%, 9 = 85–95%, 8 = 70–85%, 7 = 65–75%, 6 = 55–65%, 5 = less than 55%, N = No control, ? = unknown, - not present. Above ratings are for average conditions; results may differ with variations in weed size, temperature, rainfall, soil moisture, soil type, and soil pH.
² Effectiveness on emerged weeds only; no residual weed control from Gramoxone, Roundup or Touchdown alone.
( * = Top kill only.)