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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #109959
Title: CAN TRIPLOID HYBRID BERMUDAGRASS CULTIVARS BE WEEDS IN COTTON?

Author
item Webster, Theodore
item BEDNARZ, C - UNIVERSITY OF GEORGIA
item Hanna, Wayne

Submitted to: 1999 Georgia Cotton Research and Extention Report
Publication Type: Experiment Station
Publication Acceptance Date: 10/1/1999
Publication Date: N/A
Citation: Webster, T.M., Bednarz, C.W., Hanna, W.W. 1999. Can triploid hybrid bermudagrass cultivars be weeds in cotton? University of Georgia Cotton Research and Extension Report. p.43-46.

Interpretive Summary: Transgenic crops in general have allowed growers to more effectively manage pests. In the turfgrass industry, there is a fear that a transgenic bermudagrass cultivar could become a weed problem in other crops. To address this issue, field studies were conducted to determine the potential invasiveness and control of triploid hybrid bermudagrass cultivars in cotton. These cultivars are sterile and will not produce pollen nor seed. Plugs of two triploid bermudagrass cultivars (TifSport and TifEagle), Tifton-10 and common bermudagrass were transplanted into a cotton field and allowed to establish for four weeks. Management treatments included: cultivation, quizalofop (10 oz/a), clethodim (16 oz/a), clethodim plus glyphosate (16 oz/a and 2 pt/a), fluazifop (24 oz/a), an extreme rate of glyphosate (5 qt/a), and a nontreated control. Bermudagrass control, plug diameters, plant vigor, and cotton yields were evaluated. All herbicide treatments controlled the TifSport 86% and TifEagle 98%. Tifton-10 appeared to be the most difficult to control of the cultivars, but the labeled rate of quizalofop controlled it 85%. All herbicide treatments reduced plug diameters of TifSport, TifEagle, and common bermudagrass at least 97%, with no diameter exceeding 0.33 cm. The cultivated and nontreated control diameters were 18.9, 2.9, and 27.6 cm. The risk of invasion by triploid hybrid bermudagrass cultivars is low, however, results indicate that they can be controlled if they do escape.

Technical Abstract: A recent survey of Georgia extension agents determined that common bermudagrass was the number 12 most troublesome weed in cotton and overall the 18th most troublesome species in the nine crops sampled. Creation of transgenic bermudagrass cultivars could be beneficial to the turfgrass industry, however fears that it will become a weed in other crops persist. Studies were conducted to determine the potential invasiveness and control of sterile hybrid triploid bermudagrass cultivars in cotton. Plugs of two triploid bermudagrass cultivars (TifSport and TifEagle), Tifton-10 and common bermudagrass were transplanted into a cotton field and allowed to establish for four weeks. Treatments included: cultivation, quizalofop (10 oz/a), clethodim (16 oz/a), clethodim plus glyphosate (16 oz/a and 2 pt/a), fluazifop (24 oz/a), an extreme rate of glyphosate (5 qt/a), and a nontreated control. Bermudagrass control, plug diameters, plant vigor, and cotton yields were evaluated. All herbicide treatments controlled the TifSport 86% and TifEagle 98%. Tifton-10 appeared to be the most difficult to control of the cultivars, but the labeled rate of quizalofop controlled it 85%. All herbicide treatments reduced plug diameters of TifSport, TifEagle, and common bermudagrass at least 97%, with no diameter exceeding 0.33 cm. The nontreated control diameters were 18.9 (TifSport), 2.9 (TifEagle), and 27.6 (common) cm. The risk of invasion by triploid hybrid bermudagrass cultivars is low, however, results indicate that they can be controlled if they do escape.