Corn and soybean farmers across Indiana were surveyed in 2003 to determine the perceived importance of weeds at the state and district levels. Weeds were considered the primary crop pest by 69 to 84% of farmers, depending on district. Diseases or insects were ranked first by no more than 14% of farmers and nematodes were ranked first by no more than 11%. Giant ragweed, Canada thistle, common lambsquarters, common cocklebur, and velvetleaf were considered the most problematic summer annual and perennial weeds statewide. Chickweed, horseweed, dandelion, and henbit were considered the most problematic winter annual weeds statewide. However, no weed species was listed by more than 41% of farmers statewide suggesting that relatively unique weed management problems may exist on many farms. Also, the perceived importance of most weed species varied substantially among Indiana's nine districts. For example, velvetleaf was not listed as a problematic weed by any farmers in three districts. Burcucumber was not considered a statewide problem but was listed among the top three weeds by 14 and 16% of farmers in two southern districts. This survey supports the idea that educational programs focused on weed management should be tailored to geographic regions within Indiana.
Nomenclature: Burcucumber, Sicyos angulatus L. #3 SIYAN; Canada thistle, Cirsium arvense (L.) Scop. # CIRAR; chickweed, Stellaria media (L.) Vill. # STEME; common cocklebur, Xanthium strumarium L. # XANTH; common lambsquarters, Chenopodium album L. # CHEAL; dandelion, Taraxacum officinale Weber in Wiggers # TAROF; giant ragweed, Ambrosia trifidia L. # AMBTR; henbit, Lamium amplexicaule L. # LAMAM; horseweed, Conyza canadensis (L.) Cronq. # ERICA; velvetleaf, Abutilon theophrasti L. # ABUTH; corn, Zea mays L.; soybean, Glycine max (L.) Merr.
Additional index words: pests, weed rankings, winter annual, summer annual, perennial, Sorghum halepense, Sorghum bicolor, # SORVU, # SORHU.
Abbreviations: GDD, growing degree days; IASS, Indiana Agricultural Statistics Service.