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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #201428
Title: The critical period of Bengal Dayflower (Commelina Bengalensis) control in peanut

Author
item Webster, Theodore
item Faircloth, Wilson
item FLANDERS, J - UNIV. OF GA,TIFTON,GA
item PROSKTO, E - UNIV. OF GA,TIFTON,GA
item GREY, T - UNIV. OF GA,TIFTON,GA

Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2007
Publication Date: 7/9/2007
Citation: Webster, T.M., Faircloth, W.H., Flanders, J.T., Proskto, E.P., Grey, T.L. 2007. The critical period of Bengal Dayflower(Commelina bengalensis) control in peanut. Weed Science. 55:359-364.

Interpretive Summary: Tropical spiderwort (Benghal dayflower) is an exotic invasive weed, has become a significant pest in cotton and peanut in Georgia and Florida. With a known distribution limited to five Georgia counties in 1999, tropical spiderwort was confirmed in 36 Georgia counties in 2006. Tropical spiderwort has become a significant pest due to drastic changes in crop production practices, including but not limited to: elimination of the use of PRE herbicides with soil residual activity, adoption of reduced tillage (coupled with elimination of cultivation as a weed control tactic), and reliance on glyphosate-based systems for weed control. Effective management requires knowledge of the crop stage most sensitive to the effects of tropical spiderwort interference. In 2004, the critical period of weed control (CPWC) necessary to avoid greater than 10% peanut yield loss was between 326 and 559 growing degree days (GDD) (an interval between June 8 and June 28). In 2005, the CPWC ranged from 250 to 480 GDD (an interval between June 5 and June 27). Maximum yield loss in 2005 from season-long interference of tropical spiderwort was 51%. In 2004, peanut yield was eliminated by interference with tropical spiderwort for the initial six weeks (495 GDD) of the growing season. In spite of higher tropical spiderwort population densities, greater tropical spiderwort growth, and greater peanut yield losses in 2004 than in 2005, the CPWC was a relatively similar three-week period beginning in early June, when peanut was planted in the first week of May.

Technical Abstract: Tropical spiderwort (Benghal dayflower) is among the most troublesome weeds in Georgia peanut. Field studies in 2004 and 2005 evaluated the relationship between the duration of tropical spiderwort interference and peanut yield in an effort to optimize the timing of weed control efforts. Critical period of weed control (CPWC) studies were composed of weed-free and weedy duration intervals of 2 to 10 and 2 to 7 wks after crop emergence in 2004 and 2005, respectively. Weeds were removed from peanut following these intervals. In 2004, the CPWC necessary to avoid greater than 10% peanut yield loss was between 326 and 559 growing degree days (GDD), which corresponded to an interval between June 8 and June 28. In 2005, the CPWC ranged from 250 to 480 GDD, an interval between June 5 and June 27. Maximum yield loss in 2005 from season-long interference of tropical spiderwort was 51%. In 2004, production of peanut pods was eliminated by interference with tropical spiderwort for the initial six weeks (495 GDD) of the growing season. In spite of higher tropical spiderwort population densities, greater tropical spiderwort growth, and greater peanut yield losses in 2004 than in 2005, the CPWC was a relatively similar three-week period beginning in early June, when peanut was planted in the first week of May.