Most Common and Troublesome Weeds in 2017 Results for the U.S. & Canada (202 survey responses) Most Common and Troublesome Weeds in Grass Crops, Pasture & Turf 1) corn, 2) pastures, rangeland, or other hay, 3) rice, 4) sorghum, 5) spring cereal grains, 6) turf, and 7) winter cereal grains Common weeds refer to those weeds you most frequently see. Troublesome weeds are those that are most difficult to control, but may not be widespread. WSSA’s Composite List of Weeds is used for weed common and latin names http://wssa.net/wssa/weed/composite-list-of-weeds/ Suggested citation: Van Wychen L (2017) 2017 Survey of the Most Common and Troublesome Weeds in Grass Crops, Pasture and Turf in the United States and Canada. Weed Science Society of America National Weed Survey Dataset. Available: http://wssa.net/wp-content/uploads/2017-Weed-Survey_Grass-crops.xlsx

Top 6 Weeds in Corn MOST COMMON MOST TROUBLESOME (50 survey respondents) MOST COMMON MOST TROUBLESOME 1 common lambsquarters (30)* 2 foxtail spp. (27) 3 waterhemp (19) 4 morningglory spp. (17) pigweed spp. (17) 6 Palmer amaranth (16) 1 Palmer amaranth (21)* 2 waterhemp (20) 3 morningglory spp. (18) 4 giant ragweed (17) 5 common lambsquarters (16) 6 kochia (12) * number of survey respondents who listed the weed species as one of their top 5 weeds in this crop. - foxtail spp. included giant, green and yellow foxtail. morningglory spp. included ivyleaf morningglory. pigweed spp. included redroot and smooth pigweed and Powell amaranth.

Top 5 Weeds in Pasture, Rangeland, other Hay (39 survey respondents) MOST COMMON MOST TROUBLESOME 1 Bromus spp. (11)* Canada thistle (11) horsenettle (11) 4 dandelion (8) spiny amaranth (8) 1 Canada thistle (12)* 2 horsenettle (11) 3 leafy spurge (8) 4 Bromus spp. (7) 5 sandbur spp. (6) knapweed spp. (6) * number of survey respondents who listed the weed species as one of their top 5 weeds in this crop. Bromus spp. included downy, smooth, and Japanese brome. sandbur spp. included field sandbur. knapweed spp. included spotted, Russian, and diffuse knapweed.

Top 4 Weeds in Rice MOST COMMON MOST TROUBLESOME (10 survey respondents) MOST COMMON MOST TROUBLESOME 1 Echinochloa spp. (11)* 2 Cyperus spp. (9) 3 sprangletop spp. (7) 4 hemp sesbania (6) 1 Echinochloa spp. (10)* Cyperus spp. (10) sprangletop spp. (10) 4 red rice biotypes (6) * number of survey respondents who listed the weed species as one of their top 5 weeds in this crop. - Echinochloa spp. included barnyardgrass, junglerice and late watergrass. Cyperus spp. included rice flatsedge, yellow nutsedge and smallflower umbrella sedge. sprangletop spp. included Amazon, bearded and Nealley’s sprangletop.

Top 5 Weeds in Sorghum MOST COMMON MOST TROUBLESOME (14 survey respondents) MOST COMMON MOST TROUBLESOME 1 crabgrass spp. (10)* 2 Urochloa spp. (9) 3 Palmer amaranth (8) morningglory spp. (8) 5 johnsongrass (7) 1 Urochloa spp. (10)* 2 johnsongrass (8) Palmer amaranth (8) morningglory spp. (8) 5 Tie among 4 species (4) * number of survey respondents who listed the weed species as one of their top 5 weeds in this crop. - crabgrass spp. included large crabgrass. - Urochloa spp. included broadleaf signalgrass and Texas and browntop millet. morningglory spp. included ivyleaf and pitted morningglory.

Top 5 Weeds in Spring Cereal Grains (20 survey respondents) MOST COMMON MOST TROUBLESOME 1 common lambsquarters (12)* 2 mustard spp. (11) 3 wild oat (10) 4 wild buckwheat (8) foxtail spp. (8) 1 wild oat (11)* 2 kochia (8) wild buckwheat (8) Canada thistle (8) 5 Galium spp. (6) * number of survey respondents who listed the weed species as one of their top 5 weeds in this crop. - mustard spp. included rapeseed (volunteer canola), wild mustard, wild radish and shepherd’s-purse. - foxtail spp. included green foxtail. Galium spp. included catchweed bedstraw (cleavers) and false cleavers.

Top 5 Weeds in Turf MOST COMMON MOST TROUBLESOME (28 survey respondents) MOST COMMON MOST TROUBLESOME 1 crabgrass spp. (26)* 2 dandelion (20) 3 clover spp. (14) 4 annual bluegrass (10) 5 Tie among 2 species (6) 1 ground ivy (9)* Paspalum spp. (9) 3 bermudagrass (8) nutsedge spp. (8) dandelion (8) * number of survey respondents who listed the weed species as one of their top 5 weeds in this crop. crabgrass spp. included large, smooth and southern crabgrass. Paspalum spp. Included dallisgrass, field paspalum and bahiagrass. - clover spp. included white clover. nutsedge spp. included yellow and purple nutsedge.

Top 5 Weeds in Winter Cereal Grains (41 survey respondents) MOST COMMON MOST TROUBLESOME 1 mustard spp. (31)* 2 Lamium spp. (23) 3 Bromus spp. (18) Italian ryegrass (18) 5 common chickweed (10) 1 Bromus spp. (19)* Italian ryegrass (19) 3 annual bluegrass (11) 4 cereal (feral) rye (10) 5 Tie among 3 species (9) * number of survey respondents who listed the weed species as one of their top 5 weeds in this crop. mustard spp. included flixweed, shepherd’s-purse, field pennycress, wild radish, blue, wild, and tumble mustard, and pinnate tansymustard. Lamium spp. included henbit and purple deadnettle. Bromus spp. included downy, smooth and Japanese brome, and cheat.

Top 10 Most Common Weeds among all Grass Crops, Pasture, & Turf (202 total survey respondents) MOST COMMON * number of survey respondents who listed the weed species as one of their top 5 weeds. crabgrass spp. included large, smooth and southern crabgrass. mustard spp. included shepherd’s-purse, flixweed, rapeseed (volunteer canola), wild radish, field pennycress, wild, blue, and tumble mustard, pinnate tansymustard, and yellow and London rocket. foxtail spp. included green, giant, and yellow foxtail. Bromus spp. included downy, smooth, and Japanese brome, cheat, and rescuegrass. Lamium spp. included henbit and purple deadnettle. morningglory spp. included ivyleaf and pitted morningglory. 1 crabgrass spp. (55)* 2 common lambsquarters (49) mustard spp. (49) 4 foxtail spp. (44) 5 Bromus spp. (37) 6 kochia (36) 7 dandelion (31) 8 Lamium spp. (30) 9 Palmer amaranth (26) morningglory spp. (26)

Top 10 Most Troublesome Weeds among all Grass Crops, Pasture, & Turf (202 total survey respondents) MOST TROUBLESOME 1 Bromus spp. (32)* Canada thistle (32) 3 Palmer amaranth (31) kochia (31) 5 morningglory spp. (26) 6 foxtail spp. (25) field bindweed (25) 8 waterhemp (24) 9 Italian ryegrass (23) 10 nutsedge spp. (22) common lambsquarters (22) * number of survey respondents who listed the weed species as one of their top 5 weeds. Bromus spp. included downy, smooth, and Japanese brome, cheat, and rescuegrass. morningglory spp. included ivyleaf, pitted, and tall morningglory. foxtail spp. included green, giant, and yellow foxtail. nutsedge spp. included yellow and purple nutsedge.