Global Climate Change: Potential Impacts of Increasing Temperature On the Invasive Weed Benghal Dayflower (Commelina benghalensis L.).

Global climate change is expected to have far-reaching impacts on agriculture. Higher temperatures, potentially, could increase growth and competitiveness of weed species, especially those with tropical origins that have high temperature optima. Benghal Dayflower (Commelina benghalensis L.) is an invasive, noxious weed that is a serious threat to agriculture in the southeastern U.S. Its tolerance to Glyphosate, ability to produce both aerial and subterranean seeds and to regenerate from stem fragments make it extremely difficult to control. It is native to tropical Asia, Africa and the Pacific Islands and has been established in Florida since the early years of this century. It is now the most troublesome weed in cotton and soybean in Georgia, and recent observations suggest it is moving northward into North Carolina. The purpose of this research program is to develop a model that will predict the spread of Benghal dayflower northward into new habitats. The most current experiments were conducted in controlled environments to evaluate the response of Benghal dayflower to a range of day/night temperatures and photoperiods. Results show that growth is maximized at day/night temperature of 35/28 C irrespective of the day length, apparently reflecting its tropical origins. Aerial and subterranean seed production is more variable, suggesting substantial reproductive plasticity. Research in 2009 will define responses to other climatic and cultural factors and their interactions.