PACE Turf - Turfgrass Information Center

Diseases

Fungicides for Control of Anthracnose on Annual Bluegrass Greens

Summary: In a replicated field trial at San Diego Country Club, Chula Vista, CA, monthly applications of Heritage at 0.2 and 0.4 oz/1000 sq ft and Lynx at 1.5 oz/1000 sq ft provided excellent protection against anthracnose (Colletotrichum graminicola) attack on annual bluegrass greens when compared to Bayleton at 4.0 oz/1000 sq ft or the non-treated control plots. Less than acceptable performance of Bayleton may have been due to the monthly application interval (as opposed to a biweekly application interval).

Printable version of full report

Principal Investigators: Wendy Gelernter, Ph.D. and Larry J. Stowell, Ph.D., CPPP, CPAg

Cooperator: Gary Dalton, San Diego Country

Club Sponsors:  David Ross, Zeneca and Gary Braness, Bayer

Progress in Understanding Rapid Blight of Cool Season Turf

Bottom line: Since 1995, when it was discovered in PACE’s laboratory to be a new pathogen of cool season turf, the identity of the disease that came to be known as rapid blight was hard to pin down, with some experts identifying it as a primitive chytridiomycete fungus and others as a protozoan. Success was finally achieved in March, 2003, when the laboratories of Dr. Mary Olsen and Dr. Robert Gilbertson confirmed that rapid blight is caused by an obscure microorganism that has features of both fungi and protozoans and is known as Labyrinthula. Until the discovery of its role in turf disease, Labyrinthula had been most frequently found infecting plants in marine environment such as seagrass, diatoms and algae. Further progress has been made in work by Drs. Bruce Martin, Mary Olsen and Dave Kopec in determing which turfgrass species are susceptible or tolerant to rapid blight infection. Additional field research has confirmed the activity of mancozeb (Fore, Protect) – either alone or in combination with trifloxystrobin (Compass) or pyraclostrobin (Insignia) for preventive control of this disease.

Printable version of full report PACE Insights 2003 Vol. 9 No. 3

by Larry J. Stowell, Ph.D. and Wendy Gelernter, Ph.D.

A New Disease of Annual Bluegrass, Ryegrass and Poa trivialis

Bottom line: A new disease of cool season turf was first diagnosed in California, in 1995 from Poa annua greens. Since that time, the disease has been observed in 7 different states, and in addition to Poa annua, it has caused serious damage to Poa trivialis and Lolium perenne (perennial ryegrass) used to overseed greens, tees, fairways and roughs. The disease, which is caused by an unusual, single-celled organism that grows inside the leaf cells of turf plants, has tentatively been identified as a chytridiomycete fungus. The frequency with which this disease occurs seems to have escalated in the past few years, causing severe yellowing and death of acres of overseeded turf, and increasingly severe damage to Poa annua greens. Because this disease has not been studied in the past, it’s management is an unsolved question, although the fungicide mancozeb appears to have at least ome ability to prevent widespread damage. And preliminary data from Clemson University suggests that products such as trifloxystrobin (Compass) and the yet to be registered product pyraclostrobin (Insignia) can actually control the disease curatively. A more comprehensive management program will be developed during the next ear, based on a collaboration between Clemson University and the PACE Turfgrass Research Institute.

The common name for this disease is rapid blight.

Printable version of full report PACE Insights Vol. 7 No.11

by Larry J. Stowell, Ph.D. and Wendy Gelernter, Ph.D.

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