The goal of our research program is to lower the non-target impacts of pest management in turfgrass and urban landscapes. The turfgrass industry contributes significantly to the Wisconsin economy, employing nearly 40,000 people with a $2.4 billion impact on the state economy according to a 2010 report by the Golf 20/20 Foundation. However, intensively managed turfgrass sites such as golf courses must meet client expectations to near perfection and often rely heavily on pesticide applications to meet these expectations. In addition, some home lawns, public parks, and athletic fields also rely on repeated pesticide applications to produce flawless turfgrass surfaces. These intensive pesticide applications can have a range of negative human and environmental health effects including high toxicity to aquatic organisms, alteration of soil microbial activity, decrease in pollinator populations, and endocrine disruption in humans. As an extension specialist with a relatively small research appointment, our program must conduct high quality and client-relevant research that can be disseminated through our extension program. To accomplish this we focus our research on three areas; precision disease management using predictive models, pesticide fate and impact on turfgrass landscapes, and the turfgrass microbiome. Research in each area includes both fundamental and applied objectives to gain a broad biological understanding of the system with the intent of developing pest management recommendations for the turfgrass industry that are both effective and reduce non-target impacts.

Townsend, R.V., Millican, M.D., Smith, D., Nangle, E., Hockemeyer, K., Soldat, D., Koch, P.L. 2021. Dollar spot suppression on creeping bentgrass in response to repeated foliar nitrogen applications. Plant Disease (Accepted).

Hockemeyer, K., Koch, P.L. 2021. Field evaluations and in vitro sensitivity of Microdochium nivale to succinate dehydrogenase (SDHI) fungicides. International Turfgrass Research Journal (Accepted).

Rioux, R.A., Stephens, C.M., Koch, P.L., Kabbage, M., Kerns, J.P. 2020. Identification of a tractable model system and oxalic acid-dependent symptom development of the dollar spot pathogen Clarireedia jacksonii. Plant Pathology: Early View. https://doi.org/10.1111/ppa.13319

Koch, P.L., Hockemeyer, K., Buczkowski, E. 2020. Evaluating biological and oil-based fungicides for dollar spot suppression on turfgrass. Agronomy Journal: Early View. https://doi.org/10.1002/agj2.20407

Groben, G. Clarke, B.B., Murphy, J. Koch, P.L., Crouch, J., Lee, S., Zhang, N. 2020. Real-time PCR detection of Clarireedia, spp., the causal agents of dollar spot in turfgrasses. Plant Disease 104: 3118-3123. https://doi.org/10.1094/PDIS-04-20-0726-RE

Braun, R.C., Patton, A.J., Watkins, E., Koch, PL., Anderson, N.P., Bonos, S.A., Brilman, L.A. 2020. Fine fescues: a review of the species, their improvement, production, establishment, and management. Crop Science 60: 1142-1187. https://doi.org/10.1002/csc2.20122

Townsend, R.V., Rioux, R.A., Kabbage, M., Stephens, C., Kerns, J.P., Koch, P.L. 2020. Oxalic acid production in Clarireedia jacksonii is dictated by pH, host tissue, and xylan. Frontiers in Microbiology 11: 1732. https://doi.org/10.3389/fmicb.2020.01732

Kabbage M., Piotrowski, J.S., Thill, E., Westrick, N.M., Ralph, J., Hockemeyer, K., Koch, P.L. 2020. Poacic acid suppresses dollar spot and snow mould in amenity turfgrass. Plant Pathology 69: 112-119. https://doi.org/10.1111/ppa.13099

Hockemeyer, K., Koch, P.L. 2019. Alternative and low-use-rate herbicides offer similar levels of weed control to current standards in turfgrass lawns in the upper Midwest. Crop, Forage, and Turfgrass Management 5: 1-6. https://doi.org/10.2134/cftm2019.05.0042

Kaminski, J.E., Russell, T., Koch, P.L. 2019. First report of Ophiosphaerella agrostidis infecting creeping bentgrass in Wisconsin. Plant Disease 103:2129. https://doi.org/10.1094/PDIS-02-19-0415-PDN

Bier, P.V., Persche, M., Koch, P., Soldat, D.J. 2018. A long term evaluation of differential potassium fertilization of a creeping bentgrass putting green. Plant Soil 431: 303-316. https://doi.org/10.1007/s11104-018-3765-8

Koch, P.L., Hugie, K., Watkins, E. 2018. Resistance of prairie junegrass and tufted harigrass germplasm to diseases common in temperate low-input turfgrass systems. Plant Health Progress 19: 310-318. org/10.1094/PHP-05-18-0022-RS

Smith, D.L. and Kerns, J.P., Walker, N.R., Payne, A.F., Horvath, B., Inguagiato, J., Kaminski, J., Tomaso-Peterson, M., Koch, P.L. 2018. Development and validation of a weather-based warning system to advise fungicide application to control dollar spot on turfgrass. PLOS One. https://doi.org/10.1371/journal.pone.0194216

Karakkat, B., Hockemeyer, K., Koch, P.L. 2018. Detection of root-infecting fungi on cool-season turfgrasses using loop-mediated isothermal amplification and recombinase polymerase amplification. J Microbiol Methods 151: 90-98. doi: 10.1016/j.mimet.2018.06.01

Karakkat, B., Jackson, V., Koch, P.L. 2018. Incidence and distribution of Puccinia coronata and P. graminis on turfgrass in the Midwestern United States. Plant Disease 102(5): 955-963. org/10.1094/PDIS-09-17-1353-RE

Koch, P.L., Soldat, D.J., Horgan, B.P., Bauer, S.J., Patton, A.J. 2017. The Great Lakes School of Turfgrass Science: A Nine-State Collaboration to Improve the Turfgrass Short Course. Journal of Extension 55(3): https://www.joe.org/joe/2017june/iw4.php

Reedich, L.M., Millican, M.D., Koch, P.L. 2017. Temperature impacts on soil microbial communities and potential implications for the biodegradation of turfgrass pesticides. Journal of Environmental Quality 46(3): 490-497. doi: 10.2134/jeq2017.02.0067.

Koch, P.L. 2016. Optimal fungicide timing for suppression of Typhula blight under winter covers. Agronomy Journal 108: 1-6. Doi: 10.2134/agronj2016.04.0241

Koch, P.L., Stier, J. C., Kerns, J.P. 2015. Snow cover has variable effects on persistence of fungicides and their suppression of microdochium patch on amenity turfgrass. 2015. Plant Pathology. doi: 10.1111/ppa.12379

Koch, P.L., Kerns, J.P. 2015. Temperature influences persistence of chlorothalonil and iprodione on creeping bentgrass foliage. Plant Health Progress. doi: 10.1094/PHP-RS-15-00012. Selected as an Editor’s Pick.

Koch, P.L., Stier, J. C., Senseman, S. A., Sobek, S., Kerns, J.P. 2013. Modification of commercially-available ELISA assays to determine chlorothalonil and iprodione concentrations on golf course turfgrass. Crop Protection 54(12): 35-42.

Koch, P.L., Kerns, J.P. 2012. Impact of novel fungicide timings on the development of snow mold and dollar spot on golf course turfgrass. International Turfgrass Research Society Journal 12: 97-101.

Koch, P.L., Kerns, J.P. 2012. Relative resistance of creeping bentgrass cultivars to Sclerotinia homoeocarpa and Typhula incarnata. Applied Turfgrass Science doi: 10.1094/ATS-2012-1022-01-RS.

Koch, P. L., Kerns, J. P., Stier, J. C. 2009. Spring time fungicide applications delay and reduce dollar spot disease of turfgrass in Wisconsin. International Turfgrass Society Research Journal 11(I): 241-252.

Koch, P. L., Grau, C. G., Jo, Y. K., Jung, G. 2009. Thiophanate-methyl and propiconazole sensitivity in Sclerotinia homoeocarpa populations from golf courses in Wisconsin and Massachusetts. Plant Disease 93(1): 100-105.