INVASIVE WEED ALERT - TROPICAL SPIDERWORT (COMMELINA BENGHALENSIS): A TROPICAL INVADER THREATENS AGROECOSYSTEMS OF THE SOUTHERN UNITED STATES

Authors: Webster, Theodore; BURTON, MICHAEL - NC STATE UNIVERSITY; CULPEPPER, A - UNIVERSITY OF GEORGIA; YORK, A - NC STATE UNIVERSITY; PROSTKO, ERIC - UNIVERSITY OF GEORGIA

Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/18/2005
Publication Date: 1/1/2005
Citation: Webster, T. M., Burton, M. G., Culpepper, A. S., York, A. C., Prostko, E. P. 2005. Invasive Weed Alert - Tropical spiderwort (Commelina benghalensis): A tropical invader threatens agroecosystems of the southern United States. Weed Technology. 19:501-508.

Interpretive Summary: Tropical spiderwort (more appropriately called Benghal dayflower) poses a serious threat to crop production in the southern USA. This Weed Alert reviews the biology, ecology, and management of tropical spiderwort in the US and in its native and invaded habitats around the world. While tropical spiderwort has been present in the USA for over seven decades, it has only recently become a pest in agricultural fields. Identified as an isolated weed problem in 1998, tropical spiderwort became the most troublesome weed in Georgia cotton by 2003. Contributing to the significance of tropical spiderwort as a troublesome weed is the lack of control afforded by most commonly used herbicides, especially glyphosate. Vegetative growth and flower production of tropical spiderwort was optimized between 30 and 35C, but growth was sustained over a range of 20 to 40C. These temperatures are common throughout much of the USA during summer months. At the very least, it appears that tropical spiderwort may be able to co-occur with cotton throughout the southeastern USA. While Georgia is the second largest cotton state (in terms of planted hectares), Georgia represents only 11% of the 4.8 million ha of U.S. cotton. The environmental limits of tropical spiderwort have not yet been determined. However, the rapid spread through Georgia and naturalization in North Carolina, coupled with its tolerance to current management strategies and its aggressive growth habit, make tropical spiderwort a significant threat to agroecosystems in the southern USA.

Technical Abstract: Tropical spiderwort (more appropriately called Benghal dayflower) poses a serious threat to crop production in the southern USA. While tropical spiderwort has been present in the USA for over seven decades, it has only recently become a pest in agricultural fields. Identified as an isolated weed problem in 1999, tropical spiderwort became the most troublesome weed in Georgia cotton by 2003. Contributing to the significance of tropical spiderwort as a troublesome weed is the lack of control afforded by most commonly used herbicides, especially glyphosate. Vegetative growth and flower production of tropical spiderwort was optimized between 30 and 35C, but growth was sustained over a range of 20 to 40C. These temperatures are common throughout much of the USA during summer months. At the very least, it appears that tropical spiderwort may be able to co-occur with cotton throughout the southeastern USA. While Georgia is the second largest cotton state (in terms of planted hectares), Georgia represents only 11% of the 4.8 million ha of U.S. cotton. The environmental limits of tropical spiderwort have not yet been determined. However, the rapid spread through Georgia and naturalization in North Carolina, coupled with its tolerance to current management strategies and its aggressive growth habit, make tropical spiderwort a significant threat to agroecosystems in the southern USA.