Distribution of Field Bindweed and Hedge Bindweed in the USA

A survey of weed specialists and herbaria was conducted by mail with telephone follow-up in 1994 and 1995 to determine the distribution, abundance, and economic importance of field bindweed (Convolvulus arvensis L.) and hedge bindweed [Calystegia sepium (L.) R Br.] (Convolvulaceae) in the continental USA. Field bindweed occurs at densities regarded as serious (greater than 1000 acres/county) in 957 counties, moderate (between 250 and 1000 acres/county) in 845 counties, and low (less than 250 acres/county) in 573 counties in 47 of the 48 contiguous states. Only Florida and the southern parts of states from South Carolina to Texas do not report its presence. Field bindweed infestations have increased since 1970 in several western states but have decreased in importance in most Great Plains states. Based on detailed crop loss data for 10 states containing 52% of the seriously infested counties, we estimated the value of crop losses due to field bindweed in the USA at more than $377 million/yr. Hedge bindweed occurs at densities regarded as serious in 101 counties, moderate in 1109 counties, and low in 553 counties in 43 states. Although not as widespread as field bindweed, hedge bindweed appears to have increased in abundance since 1969 and continues to be a localized problem in the midwestern and eastern USA. Research QuestionChanges in crop production practices during the past 30 yr have increased the economic importance of bindweed in some crops and geographic areas while reducing it in others. This report offers useful information for developing regulatory and economic programs, establishing research priorities and implementing research programs. The purposes of this project are to document the current distribution of field bindweed and hedge bindweed in the USA at the county level and to estimate a yearly economic cost in lost agricultural commodities in the USA due to infestations of field bindweed. Literature SummaryField bindweed and hedge bindweed are widespread and aggressive weeds in at least 32 crops in the USA. They compete for soil moisture and nutrients and their vine-like stems reduce harvest efficiency. In row crops, these deep-rooted perennials reduce yields by 20 to 75% in cereal crops and 50 to 80% in row crops. Field bindweed originated in Europe or Asia but was accidentally introduced into the USA during the early 1700s. It rapidly spread across the USA during the 1800s and soon became a major weed in many states. By 1975, it was present in most of the 48 contiguous states and of special economic importance in the Great Plains. Hedge bindweed, a closely related species, is troublesome east of the Rocky Mountains but less important than field bindweed. Study DescriptionOver 100 weed specialists in the continental USA were asked to report the distribution and degree of infestation for field bindweed and hedge bindweed in each county in their respective states. Infestations were ranked as serious, greater than 1000 acres infested per county; moderate, less than 1000 acres infested but more than 250 acres; or low, less than 250 acres infested per county. Maps were constructed from the data reported. Crop loss values due to field bindweed infestations were estimated from data collected, 1994 agriculture surveys conducted by a few states, and personal communications with state weed specialists. Applied QuestionsHow serious is the field bindweed problem in the USA? Field bindweed occurs in 47 of the 48 contiguous states in the USA and in 78% of the counties. Only Florida and the southern parts of states from South Carolina to Texas do not have this weed. Thirty-nine percent of all counties were ranked as having serious infestations (greater than 1000 acres; Fig. 1). Since 1970, infestations have increased in some western states but have decreased in the Great Plains, while remaining a serious problem. Field bindweed can increase in severity where fields are irrigated, no-till practices are employed, or land is removed from the Conservation Reserve Program. Data from 10 selected states were used to project economic losses due to field bindweed. We estimate crop losses of $377.8 millio/yr due to this weed. How serious is the hedge bindweed problem in the USA? Hedge bindweed occurs in 57% of the counties in 43 states but severely infests only 6%. It continues to be a spotty, but significant problem in the Midwest and eastern states; however, it is not as great a problem as field bindweed.