In soybeans, 63% of the people said that common lambsquarters was their most troublesome weed, which confirms much of our recent discussion. Common lambsquarters was ranked at the top at all of our meeting sites across the state. Giant ragweed, dandelion, waterhemp and common ragweed round out the top five on the list. Giant ragweed was specifically noted at our Janesville, Arlington, and Platteville meeting locations. Grass weeds are generally not a current problem in soybeans in Wisconsin.

In corn, a more diverse variety of weeds were mentioned as troublesome as compared with the weeds mentioned in soybeans. Giant ragweed was the most frequent response in being troublesome and again was primarily mentioned in the south and west (Janesville, Arlington, Platteville, and Sparta). Grass weeds are more of a problem in corn and crabgrass was the most frequently named. All regions of the state mentioned crabgrass, but it was the highest ranking weed only at our Fond du Lac meeting site (14 of 30 responses). Common lambsquarters, foxtails, and velvetleaf round out the top five weeds in corn. Common lambsquarters was mentioned across the state, but foxtails seemed to be more of a concern in the east (Fond du Lac and Green Bay) and velvetleaf in the north (Green Bay and Marshfield).

Table 1. Most troublesome weeds in 2005 (ranked in order by number of responses).
in corn	no.		in soybean	no.
Giant ragweed	57		Lambsquarters	178
Crabgrass	45		Giant ragweed	26
Lambsquarters	42		Ragweed	11
Foxtail	29		Dandelion	11
Velvetleaf	22		Waterhemp	10
Quackgrass	18		Common ragweed	8
Woolly cupgrass	15		White cockle	5
Waterhemp	14		Velvetleaf	4
Dandelion	12		Foxtail	3
Ragweed	10		Crabgrass	3
Wild proso millet	8		Volunteer corn	3
Common ragweed	5		Pigweed	3
Canada thistle	5		Nightshade	3
Shattercane	4		Wild proso millet	2
Sandbur	3		Horseweed	2
Pigweed	3		Yellow nutsedge	2
Yellow nutsedge	3		Canada thistle	2
Horseweed	2		Hairy galinsoga	2
Chickweed	2		Woolly cupgrass	1
Alfalfa	2		Quackgrass	1
Barnyardgrass	1		Wild radish	1
Witchgrass	1		Total responses	281
Burdock	1
Wild radish	1
Horsetail	1
Hemp dogbane	1
White cockle	1
Total responses	308

This information helps to confirm many of our beliefs about some of the toughest weeds in Wisconsin and provides a warning about less common weeds that are also causing problems.