Entomology and Plant Pathology

Dr. Nathan Walker, Professor

B.S., Bloomsburg University, 1993

M.S., Clemson University, 1996

Ph.D., University of Arkansas, 1999



ENTO/PLP 3663     Turfgrass Integrated Pest Management
PLP 5004 Plant Nematology
ENTO/PLP 5524 Integrated Pest Management


My research program is focused on the integrated management of turfgrass pests in Oklahoma. Research projects have examined the biology and management of nematodes, insects, and turfgrass diseases. More recent efforts have been directed at the biology of May/June beetles, Spring dead spot of bermudagrass, and fungal biodiversity in the roots of native prairie grasses.

Refereed Publications:

Caasi, O. C., Walker, N. R., Marek, S. M., Enis, J. N., and Mitchell, T. K. 2010. Infection and colonization of turf-type bermudagrass by Ophiosphaerella herpotricha expressing green (GFP) or red (tdTomato) fluorescent proteins. Phytopath. 91:(In Press).

Walker, N. R., 2009. Influence of fungicide application timings on the management of bermudagrass spring dead spot caused by Ophiosphaerella herpotricha. Plant Dis. 94:1341-1345.

Walker N. R., S. M. Marek, and D. L. Smith. 2009. Fungal biodiversity in bermudagrass (Cynodon dactylon × transvaalensis) inoculated with Ophiosphaerella herpotricha or Gaeumannomyces graminis var. graminis. Inter. Turf. Soc. Res. J. 11: 283-292.

Tredway, L. P., Tomaso-Peterson, M., Perry, H., and Walker, N. R. 2009. Spring dead spot of bermudagrass: A challenge for researchers and turfgrass managers. Plant Health Progress at http://www.plantmanagementnetwork.org. (doi:10.1094/PHP-2009-0710-01-RV).

Doskocil, J. P., Walker, N. R., Bell, G. E., Marek, S. M., Reinert J. A., and Royer. T. A. 2008. The species composition and seasonal occurrence of Phyllophaga (Coleoptera:Scarabaeidae) infesting intensely managed bermudagrass in Oklahoma. J. Econ Entomol. 101:1624-1632.

Marek, S. M., Moncrief, I. R., and Walker, N. R. 2008. First report of dollar spot of buffalograss. Plant Dis. 92:1249.

Walker, N. R., Mitchell, T. K., Morton, A. N., and Marek, S. M. 2006. Influence of temperature and time of year on colonization of bermudagrass roots by Ophiosphaerella herpotricha. Plant Dis. 90:1326-1330.

Marek, S. M., Muller R. A., and Walker, N. R., 2006. First Report of Ergot of Bermudagrass Caused by Claviceps cynodontis in Oklahoma. Plant Dis. 90:376

Walker, N. R., Zhang, H., and Martin, D. L. 2005. Potential management approaches for the sting nematode in bermudagrass sod production. Inter. Turf. Soc. Res. J. 10:793-796.

Woodward, J. E., Walker, N. R., Dillwith, J. W., Zhang, H., and Martin, D. L. 2005. The potential influence of fungicides on a nematophagous fungus in simulated putting green soil. Ann. Appl. Bio. 146:115-121

Driskel, B. A., Doss, P., Littlefield, L. J., Walker, N. R., and Verchot-Lubicz, J. 2004. Soilborne wheat mosaic virus movement protein and RNA and Wheat spindle streak mosaic virus coat protein accumulate inside resting spores of their vector Polymyxa graminis. Mol. Plant- Micro Inter.17:739-748.

Royer, T. A., and Walker, N. R. 2004. The effects of predation by thief ants Solenopsis molesta on survival of black cutworm larvae Agrotis ipsilon in a turfgrass ecosystem. Southwest Ento. 29:31-38.

Koenning, S. R., Kirkpatrick, T. L., Starr, J. L., Wrather, J. A., Walker, N. R., and Mueller, J. D. 2004. Plant-parasitic nematodes attacking cotton in the United States: old and emerging production challenges. Plant Dis. 88:100-113.

Crow, W. T., and Walker, N. R. 2003. Diagnosis of Peltamigratus christiei, a Plant-Parasitic Nematode Associated with Warm-Season Turgrasses in the Southern United States Plant Health Progress at http://www.plantmanagementnetwork.org.

Koh, K., Bell, G.E., Martin, D.L., and Walker, N. R. 2003. Shade and airflow restriction effects on creeping bentgrass golf greens. Crop Sci. 43:2182-2188.

Walker, N. R., Goad, C., Zhang, H., and Martin, D. L. 2002. Factors associated with populations of plant parasitic nematodes in bentgrass putting greens. Plant Dis. 86:764-768.

Walker, N. R., Kirkpatrick, T. K., and Rothrock, C. S. 2000. Influence of Meloidogyne incognita and Thielaviopsis basicola populations on early-season disease development and cotton growth. Plant Dis. 84:449-453.

Walker, N. R., Kirkpatrick, T. K., and Rothrock, C. S. 1999. The effect of temperature and the histopathology of the interaction between Meloidogyne incognita and Thielaviopsis basicola on cotton (Gossypium hirsutum). Phytopathology 89:613-617.

Walker, N. R., Kirkpatrick, T. K., and Rothrock, C. S. 1998. The interaction between the root-knot nematode (Meloidogyne incognita) and black root rot (Thielaviopsis basicola) on cotton (Gossypium hirsutum). Journal of Nematology. 30:415-422.

Book Chapter:

Giles, K. L. and Walker, N. R. 2009. Dissemination and Impact of IPM Programs in US Agriculture, p. 481-505. In: R. Peshin and A. K. Dhawan (eds). Integrated Pest Management: Dissemination and Impact. Springer Netherlands.

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