Detecting Cutleaf Teasel (Dipsacus laciniatus) along a Missouri Highway with Hyperspectral Imagery Diego J. Bentivegna, Reid J. Smeda, and Cuizhen Wang* Cutleaf teasel is an invasive, biennial plant that poses a significant threat to native species along roadsides in Missouri. Flowering plants, together with understory rosettes, often grow in dense patches. Detection of cutleaf teasel patches and accurate assessment of the infested area can enable targeted management along highways. Few studies have been conducted to identify specific species among a complex of vegetation composition along roadsides. In this study, hyperspectral images (63 bands in visible to near-infrared spectral region) with high spatial resolution (1 m) were analyzed to detect cutleaf teasel in two areas along a 6.44-km (4-mi) section of Interstate I-70 in mid Missouri. The identified classes included cutleaf teasel, bare soil, tree/shrub, grass/other broadleaf plants, and water. Classification of cutleaf teasel reached a user’s accuracy of 82 to 84% and a producer’s accuracy of 89% in the two sites. The conditional k value was around 0.9 in both sites. The image-classified cutleaf teasel map provides a practical mechanism for identifying locations and extents of cutleaf teasel infestation so that specific cutleaf teasel management techniques can be implemented. Nomenclature: Cutleaf teasel, Dipsacus laciniatus L. Key words: Roadside, hyperspectral remote sensing, weed detection. Invasive weeds are highly competitive and spread quickly in most habitats (Czarapata 2005). For many invasive plants, distributions are not homogenous in natural areas. Instead, those species often aggregate into patches depending on seed dispersal, soil adaptation, microclimate, and topography (Shaw 2005a). Management of invasive weeds is a major challenge for land managers primarily because of limited resources and diverse patterns of weed distribution. Cutleaf teasel (Dipsacus laciniatus L.) is an invasive, noxious weed in Missouri. It was first introduced in the 1840s from France for the textile industry in New York to align wool fibers (Terres and Ratcliffe 1979). The spread of cutleaf teasel has been facilitated by the construction of the interstate highway systems (Solecki 1993). As a biennial plant, cutleaf teasel grows as a rosette in the first year and flowers during the summer of the next year. A single flowering plant may produce more than 33,000 seeds yr 21 (Bentivegna 2006), which could be dispersed up to 1.5 m (4.9 ft) around the parent plants (Werner 1975). Seed dispersal can also be facilitated by mowing or floating on water (Solecki 1993). As flowering plants die, open areas are filled by existing rosettes, as well as by new seedlings emergent in infested areas. Seedling emergence is relegated primarily to spring and fall (Bentivegna 2006). Rosette plants produce a dense canopy that ultimately excludes desirable species. Dense patches of cutleaf teasel aggressively colonize low maintenance areas, such as roadside rights-of-way, which often serve as seed-dispersal corridors (Hoffman and Kearns 1997; Solecki 1993). Tall, flowering plants along highways can reduce traffic visibility and increase hazards to motorists (R. Swanigan, personal communication). Cutleaf teasel reduces the diversity of native, desirable species and prominent grasses, such as tall fescue [Lolium arundinaceum (Schreb.) S.J. Darbyshire]. Taproots of cutleaf teasel reduce the infiltration of water and increase water erosion compared with the presence of grasses (Lacey et al. 1989). Therefore, control of cutleaf teasel is needed to reduce the negative effects along roadsides. Typical management of cutleaf teasel involves mowing and herbicide application. Mowing rosettes decreases the competitiveness of plants, but the time of mowing is DOI: 10.1614/IPSM-D-10-00053.1 * Graduate Student and Associate Professor, Division of Plant Science, University of Missouri, Columbia, MO 65211; Associate Professor, Department of Geography, University of Missouri, Columbia, MO 65211. Current address of first author: Research Associate, CERZOS-Center for Renewable Natural Resources of the Semiarid Region (CONICET), Camino La Carrindanga km 7, B8000FWB, Bahı ´a Blanca, Argentina. Corresponding author’s E- mail: dbentive@criba.edu.ar Invasive Plant Science and Management 2012 5:155–163 Bentivegna et al.: Detecting cutleaf teasel N 155