Crowsfoot Grass Control with Tribute Herbicide


Crowsfoot grass (Eleusine indica) is an annual warm season grass characterized by a silvery white base and dark green colour. Coarse blades grow, flat or folded, from 50 to 200mm long and 25 to 75mm wide. Mature stems can grow up to 60cm tall. Crowsfoot grass flowers are composed of 2 to 10 finger-like spikes that resemble zippers.

Host material and range

This troublesome weed, often confused with summergrass (crabgrass), is found on golf courses, lawns and sports turf areas throughout Australia, emergence begins early in spring. Traditionally, crowsfoot grass germinates when soil temperatures at the 10cm level reach 18 Co. for 24 consecutive hours. Sunlight also provides optimum germination.

As a rule of thumb, crowsfoot grass germinates three to four weeks later than summergrass, depending on the area of the country. Emergence continues throughout the summer season. Crowsfoot grass thrives in hard, compacted or poorly drained soils, as well as in high traffic areas where turfgrass cover is minimal.

Treatment Options

Crowsfoot grass has been easily controlled with Tribute herbicide in many areas. But more tropical areas have had difficulty controlling this weed after it reaches maturity in the summer and autumn. Mature crowsfoot grass has multiple tillers and an extensive root system.

Though mature weeds are more difficult to control than younger plants, university trials have shown excellent control of crowsfoot grass with Tribute herbicide, when used in a long-term program. Because some re-growth of crowsfoot grass can occur after two applications, multiple applications may be necessary. Tribute works very slowly, particularly in large plants. A third application of Tribute when the crowsfoot grass begins to re-grow will enhance control.

University studies have shown that control can be improved by adding sprayable ammonium sulphate at 4 kg per hectare. In addition, adding 1% methylated seed oil (MSO) surfactant has improved control of crowsfoot grass by 10-15% over Tribute alone.

Spot applications of Tribute can be made to hard-to control weeds under difficult conditions.

Alternating herbicides families may help with control and delay herbicide resistance. Herbicides like diclofop-methyl are labelled for crowsfoot grass control. Broadcast treatments of diclofop-methyl can be rotated with Tribute for crowsfoot grass control.

Recommendation

The most effective treatment program tested on mature crowsfoot grass on golf course greens was three applications of Tribute herbicide (2 litres per hectare.) plus sprayable ammonium sulfate at 4 kg per hectare and methylated seed oil (MSO) surfactant added at 1%, applied three times at 0, 14, and 56 days after the initial treatment.

For more information contact Jyri Kaapro at jyri.kaapro@bayer.com or visit: www.environmentalscience.bayer.com.au

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