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American Society for Horticultural Science

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Home HortTechnology Fertilizer Additive, Raking Improves Herbicide Effectiveness on Creeping Bentgrass
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FARGO, ND—Creeping bentgrass is used extensively on golf course putting greens and fairways in temperate regions. Favored for its dense growth and tolerance of low temperatures and close mowing, the turfgrass is popular among professionals. When the grass "creeps" or escapes into surrounding areas, however, it becomes an unwelcome weed; it reduces the uniformity of texture and growth habit when it invades other types of grasses.

Scientists and turfgrass professionals are seeking improved methods to selectively control creeping bentgrass when it escapes its intended boundaries. "There is very limited information on the effects of light on creeping bentgrass control using mesotrione," explained Deying Li, the corresponding author of a study that appeared in HortTechnology. "We hypothesized that increased exposure to sunlight by removing the dead tissues could result in more injury to the lower leaves by mesotrione."

Li and a team of researchers designed experiments to evaluate the effectiveness of adding urea ammonium nitrate (UAN) to mesotrione plus non-ionic surfactant (NIS) spray solution, and raking to remove dead tissues of creeping bentgrass. They conducted experiments in field plots in Fargo, North Dakota, over 2 years. The study was conducted with a split-plot design; raking was used on the whole plot while herbicide was used as the sub-plot treatment. Herbicide treatments included application of mesotrione at 56 and 70 g·ha–1 singly and sequentially with 0.25% NIS or 0.25% NIS plus 2.5% UAN solution. Sequential applications were made three times in 2-week intervals.

Results showed that mesotrione at or below an annual total rate of 210 g·ha–1applied with non-ionic surfactant, whether in one application or in three sequential applications, provided only moderate creeping bentgrass control. Removal of dead clippings and adding UAN to NIS plus mesotrione provided satisfactory creeping bentgrass control with three sequential treatments at the rate of 70 g·ha–1.

"Our research shows that, because of the growth habit of creeping bentgrass, very little volunteer creeping bentgrass will be removed when an application of mesotrione is made to the lawn height cool-season grasses," noted Li. "Turf managers may need to remove dead turf tissues by raking before sequential mesotrione treatments to improve efficacy."

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The complete study and abstract are available on the ASHS HortTechnology electronic journal web site:

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Original Article:

Urea Ammonium Nitrate Additive and Raking Improved Mesotrione Efficacy on Creeping Bentgrass
Lijuan Xie, Deying Li, Wenjuan Fang, and Kirk Howatt
HortTechnology 21:41–45. [Abstract] [Full Text] [PDF]

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