Herbicide effectiveness on common weeds in corn planted into established birdsfoot trefoil/crownvetch cover.

Table 5. Herbicide effectiveness on common weeds in corn planted into established birdsfoot trefoil/crownvetch cover. ¹

Cover Crops	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.)