Nematode Damage on Colorado Golf Greens

A partial literature review by Dr. Curtis Swift, Colorado State University Extension

Plant-parasitic nematodes were identified on several Colorado golf courses in 2008. A common symptom has been the development of yellow patches, especially during periods of high temperature.  

Nematode damage impairs the plant’s ability to take up water and nutrients from soil, thereby requiring more frequent irrigation and fertilizer applications.  Plant-parasitic nematodes that damage turfgrass favor sandy soils[i] but that does not mean they are not a problem on push-up greens. High temperatures can make nematode damage worse by decreasing plant tolerance.[ii]

Nematode damaged roots may be abnormally short and appear darkened or rotten. Often the roots will appear “cropped off” an inch or so below the soil surface. Turf symptoms include yellowing, wilting, browning, or thinning out.[iii]

 Managing P levels is critical to reducing nematode problems on turf.

Dr. Mitkowski[iv] reports that nematode assays on golf courses across the northern United States reveal nematode damage is mostly confined to Poa annua with few stands of creeping bentgrass being diagnosed with nematode-related decline. He suggests converting to creeping bentgrass if at all possible to avoid or correct nematode-related problems. 

 When converting to creeping bentgrass, high phosphorus (P) levels must be avoided as they tend to encourage Poa annua while reducing the competitive ability of creeping bentgrass.

Holt and Davis observed a decrease in bentgrass root weight when a complete fertilizer was applied as opposed to a fertilizer containing P.[v]  Low P has also been found to increase the intensity of leaf color in creeping bentgrass.[vi] Increasing P levels has been shown to encourage annual bluegrass invasion of golf greens.viii

Stowell and Kenny (http://www.paceturf.org/PTRI/Documents/050601sj.pdf) recommend a P level of between 5 ppm (Olsen test) and 30 ppm (Mehlich III) to maintain bentgrass growth while reducing the growth and spread of annual bluegrass.  

To learn more about phosphorus and plant health check out:

http://WesternSlopeGardening.org/turfgrass-fertility-needs.shtm
http://WesternSlopeGardening.org/Phosphorus_analysis_techniques.shtml
http://WesternSlopeGardening.org/mycorrhiza.shtml

[i] W. T. Crow. 2005. PLANT-PARASITIC NEMATODES ON GOLF COURSE TURF. Outlooks on Pest Management http://entnemdept.ufl.edu/Crow_RP_07.pdf

[ii] Van Gundy, S. D. 1985. Ecology of Meloidogyne spp. – Emphasis on environmental factors affecting survival and pathogenicity. in J. N. Sasser and C. C. Carter eds. Advanced Treatise on Meloidogyne Vol. 1: Biology and Control.

[iii] Crow, W. T. 2007. Nematode Management for Golf Courses in Florida.  http://edis.ifas.ufl.edu/IN124

[iv] Mitkowski, N.A. Coping with Nematodes San Fenamiphos. Turgrass Trends, December 2007.

[v] Holt, C.C. and R.L. Davis. 1948. Differential responses of ‘Arlington’ and ‘Norbeck’ bentgrasses to kinds and rate of fertilizer. Agon. J. 40:282-284.

[vi] Waddington,D.V., T.R. Turner, J.M. Duich, and E.L. Mobert. 1978. Effect of fertilization on ‘Penncross’ creeping bentgrass. Agon. J. 70:713-718.