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Manuscript herbicide to control tropical signalgrass and other weeds

By |  October 4, 2019 0 Comments

Lane Tredway, Ph.D., is a technical services manager with Syngenta. Lane has overseen numerous field experiments with Manuscript and other herbicides. You may reach Lane at for more information.

Clark Throssell headshot

Clark Throssell

Q: Briefly describe Manuscript and its fit on golf courses for weed control.

Manuscript herbicide contains the active ingredient pinoxaden and a safener, and is packaged with the surfactant Adigor. Pinoxaden is classified as an ACCase inhibitor. While ACCase herbicides have been in the agricultural market for many years, the molecule was redesigned by scientists at Syngenta for selective control of perennial and annual grasses in bermudagrass and zoysiagrass turf. As a result, Manuscript is extremely safe on bermudagrass and zoysiagrass, but should not be applied to any other warm- or cool-season turfgrass species on the golf course. Manuscript is an MSMA replacement in Florida.

Q: What weed species are most effectively controlled by Manuscript?

In Florida, tropical signalgrass (Urochloa distachya L.) is a difficult weed to control and is one of the weeds controlled by Manuscript postemergence. Two applications of Manuscript applied two to three weeks apart, with the first application made in late spring or early summer to actively growing tropical signalgrass, will provide effective control. Application of Manuscript at this time will allow bermudagrass to fill in any voids. As a result, a high-quality playing surface is ready for the fall golf season.

Manuscript also is an effective postemergent herbicide on crabgrass (Digitaria spp.) when two applications are made two to three weeks apart, with the first application made in late spring or early summer.

Dallisgrass (Paspalum dilatatum) is controlled with Manuscript, but like other herbicides, it performs best in the fall and spring. We recommend two applications on a 14- to 21-day interval starting in mid-September to mid-October or late April to May. Superintendents need persistence to control dallisgrass. It has a network of large rhizomes that allow it to recover from herbicide applications. To completely control dallisgrass, superintendents must commit to a several-year program of fall and spring herbicide applications.

For control of tropical signalgrass, crabgrass and dallisgrass, apply Manuscript at the spot treatment rate of 9.6 fl oz per 10,000 ft2.

Broadcast rates of Manuscript (9.6 to 19.2 fl oz/acre) are extremely effective for removing overseeded perennial ryegrass (Lolium perenne L.) from bermudagrass turf. It is effective at low rates and provides an abrupt transition from perennial ryegrass to the base bermudagrass. Research continues to refine Manuscript rates to remove overseeded perennial ryegrass from bermudagrass.

Q: Explain in more detail the spot treatment rate.

The advantage of the spot treatment rate is that it is higher than the broadcast rate, so it provides more effective weed control. When using the spot treatment rate, superintendents can treat only a maximum of 10,000 sq. ft. in an acre. This means superintendents must have a good handle on the distribution and area of the weed infestation to be treated.

In cases with widespread weed infestation, it may be necessary to use another herbicide to reduce the area of infestation before using Manuscript to control the remaining weeds.

Q: What tips do you have for superintendents to use Manuscript most effectively?

Manuscript is foliarly absorbed, so uniform coverage is essential. Apply Manuscript in 40 gallons of water per acre, and be sure to use Adigor (the surfactant) packaged with Manuscript. The area needs to be rain free and irrigation free for a minimum of three hours following application to allow Manuscript to be absorbed. Also, target weeds need to be green, actively growing and not under drought stress to allow Manuscript to be translocated throughout the weed.

Q: What is the environmental profile of Manuscript?

Manuscript has a reasonable environmental profile with no major environmental concerns. That said, superintendents need to read and follow all label directions, use appropriate application techniques and follow common sense safety precautions.

This is posted in Columns

About the Author: Clark Throssell, Ph.D.

Clark Throssell, Ph.D., is the former director of the Purdue University turf program as well as the former director of research for GCSAA. Throssell is the research editor for Golfdom, focusing on managing the Super Science section of the magazine and website. He also contributes his "Clark Talks Turf" column to Golfdom every month.

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