Publications and Information for Nurseries

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Information for Nurseries

NORS-DUC CDFA Best Management Practices Manual
NORS-DUC Steaming-On-the-Go Program 
NORS-DUC Plum Bud Gall Mite Host Range
NORS-DUC Field Day 2022

Recent Articles

NORS-DUC Research Helping Strawberry Grower Reduce Plastic Waste



Tomas Pastalka, Nilwala Abeysekara and Wolfgang Schweigkofler. 2023. First report of Phytophthora ramorum on Cotoneaster sp. in the USA. Plant Disease.


Raven Wienk, Marja Mostert-O’Neill, Nilwala Abeysekara, Patricia Manosalva, Barbie Freeman and Noëlani van den Berg. 2022. Genetic diversity, population structure, and clonal verification in South African avocado cultivars using single nucleotide polymorphism (SNP) markers. Tree Genetics & Genomes 

Sharifa G. Crandall, Asha M. Miles, Taejung Chung, Mara L. Cloutier, Raymond Garcia-Rodriguez, Wolfgang Schweigkofler and Estelle Couradeau. 2022. Temporal and spatial dynamics of bacterial and fungal microbiomes in nursery soils post-steaming. PhytoFrontiers.

Wolfgang Schweigkofler and Vernon Huffman. 2022. Steaming is an Efficient Way to Treat Soil, Potting Mix, Pots, and Other Supplies Infested by Plant Pathogens. Ecesis 23: 7-9

Karen Suslow, Nilwala Abeysekara, Vernon Huffman and Wolfgang Schweigkofler. 2022. Surface and Irrigation Types Have a Big Impact on Water Splash in Nurseries, Choose Wisely! Ecesis 23: 2-5

Suzanne Rooney-Latham, Cheryl Linn Blomquist, Marinell C. Soriano and Tomas Pastalka. 2022. First Report of Dieback Caused by Phytophthora ramorum on Golden Chinquapin, Chrysolepis chrysophylla, in California. Plant Disease.

Chuanxue Hong, Margery Louise Daughtrey, Matt Howle, Scott Schirmer, Kathleen Kosta, Ping Kong, T. Michaels Likins and Karen Suslow. 2022.  Rapid Decline of Calonectria pseudonaviculata Soil Population in Selected Gardens across the United States. Plant Disease. 


Ebba Peterson, Niklaus J. Grünwald and Jennifer Parke. 2021. Risk of epidemic development in nurseries from soil inoculum of Phytophthora ramorum. Phytopathology 

Fumiaki Funahashi, David M. Myrold and Jennifer L. Parke. 2021. The effects of soil solarization and application of a Trichoderma biocontrol agent on soil fungal and prokaryotic communities. Soil Science Society of America Journal

Wolfgang Schweigkofler, Tomas Pastalka, Nilwala Abeysekara, Vernon Huffman and Karen Suslow. 2021. Transmission of the invasive pathogen Phytophthora ramorum from symptomatic to healthy host plants during a five-year period in California. Plant Health Progress  

Richard M. Bostock and Tatiana V Roubtsova. 2021. The effect of applied salinity and water stress on chemical suppression of Phytophthora ramorum from soilborne inoculum in Rhododendron. The American Phytopathological Society — Plant Disease

Craig L. Ramsey, Paul C. Freebury, Debra H. Newman, Wolfgang Schweigkofler, Leland J. Cseke and Steven E. Newman. 2021. Use of Foliar Chemical Treatments to Induce Disease Resistance in Rhododendrons Inoculated with Phytophthora ramorum. Global Journal of Agricultural Innovation, Research & Development, 2021, 1-22.

Cai Hugo Thompson, Mitchell M. McCartney, Tatiana V. Roubtsova, Takao Kasuga, Susan E. Ebeler, Cristina Davis and Richard M. Bostock. 2021. Analysis of Volatile Profiles for Tracking Asymptomatic Infections of Phytophthora ramorum and other pathogens in Rhododendron. Phytopathology


Stephanie Kyne. 2020. Phytophthora Now Found in Drier Ecosystems of Marin County, CA: Is Chaparral Phytophthora’s Next Target? Proceedings of The National Conference On Undergraduate Research (NCUR), Montana State University, Bozeman MT 

Fumiaki Funahashi and Jennifer L. Parke. 2020. Soil Solarization to Eradicate Soilborne Phytophthora spp. in Container Nurseries with Surface Gravel. Journal of Environmental Horticulture 38: 158–167.

Marissa L. Layman, Craig Ramsey, Wolfgang Schweigkofler and Steven E. Newman. 2020. Field Evaluation of a Novel, Granular Soil Fumigant for Controlling Phytophthora ramorum in Field Nursery Soils. Global Journal of Agricultural Innovation, Research & Development 7,12-19

Doug Luster, Karen Suslow, Supriya Sharma, Wolfgang Schweigkofler and Vernon Huffman V. 2020. Rapid recovery and detection of Phytophthora ramorum propagules in nursery water. In: Frankel, Susan J.; Alexander, Janice M., tech. cords. Proceedings of the seventh sudden oak death science and management symposium: healthy plants in a world with Phytophthora. Gen. Tech. Rep. PSW-GTR-268. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 83-90.

Matteo Garbelotto, Tina Popenuck, Brett Hall, Wolfgang Schweigkofler, Francesco Dovana, Ruby Goldstein De Salazar, Douglas Schmidt and Laura Sims. 2020. Citizen science uncovers Phytophthora ramorum as a threat to several rare or endangered California manzanita species. Plant Disease.

Maria Socorro Serrano, Catherine Eyre and Matteo Garbelotto. 2020. Epidemiology and microevolution of Phytophthora ramorum during a controlled disease outbreak in a simulated plant production facility. Plant Pathology 69, 320-333.


Bassam A. Younis, Laura Mahoney, Wolfgang Schweigkofler and Karen Suslow. 2018. Inactivation of plant pathogens in irrigation water runoff using a novel UV disinfection system. European Journal of Plant Pathology 153, 907-914 

Wolfgang Schweigkofler, Silvia Schmidt and Christian Roschatt . 2018. Integrated pest management strategies for phytoplasma diseases of woody crop plants: possibilities and limitations. In: Beck J.J., Rering C.C., Duke S.O. (eds.) Roles of Natural Products for Biorational Pesticides in Agriculture; ACS Symposium Series #1294, Washington D.C., pp. 69-82

Timothy L. Widmer, Sheila Johnson-Brousseau, Kathleen Kosta, Sibdas Ghosh, Wolfgang Schweigkofler, Supriya Sharma and Karen Suslow. 2018. Remediation of Phytophthora ramorum-infested soil with Trichoderma asperellum isolate 04-22 under ornamental nursery conditions. Biological Control 118, 67-73. (The results of this research project were presented for a broader readership as a blog in Science Trends.)

Fumiaki Funahashi and Jennifer L. Parke. 2018. Thermal inactivation of inoculum of two phytophthora species by intermittent versus constant heat. Phytopathology 108 (7): 829-836 


Tomas Pastalka, Suzanne Rooney-Latham, Kathleen Kosta , Karen Suslow, Vernon Huffman, Sibdas Ghosh and Wolfgang Schweigkofler. 2017. Monitoring using a sentinel plant system reveals very limited aerial spread of Phytophthora ramorum from infected ornamental plants in a quarantine research nursery. Plant Health Progress 18, 9-16 

Suzanne Rooney-Latham, Cheryl L. Blomquist, Andrea Williams, Elliot Gunnison and Tomas Pastalka 2017. Identification of five new hosts of Phytophthora ramorum in an infested forest in California. Proceedings of the Sudden Oak Death sixth science symposium. Gen. Tech. Rep. GTR-PSW-255. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 83-84.


Karen Suslow and Kathy Kosta. 2016. Solarization: a simple and low-cost method for disinfesting horticultural containers. Ecesis 26, 4-7.

Takao Kasuga, Mai Bui, Elizabeth Bernhardt, Tedmund Swiecki, Kamyar Aram, Liliana M. Cano, Joan Webber, Clive Brasier, Caroline Press, Niklaus J. Grünwald, David M. Rizzo and Matteo Garbelotto 2016. Host-induced aneuploidy and phenotypic diversification in the sudden oak death pathogen Phytophthora ramorum. BMC Genomics 17:385

Fumiaki Funahashi and Jennifer L. Parke. 2016. Effects of soil solarization and Trichoderma asperellum on soilborne inoculum of Phytophthora ramorum and Phytophthora pini in container nurseries. Plant Disease 100:1-6


Lucy Rollins, Marianne Elliott and Gary Chastagner. 2015. A new method to apply Phytophthora ramorum inoculum to hosts that simulates overhead irrigation. Plant Health Progress doi:10.1094/PHP-RS-15-0008

Sacy Ditta and Adam Santiago. 2015. Molecular Analysis and Thermal Treatment of Several Phytophthora Species Causing Diseases of Ornamental Plants in California. Proceedings of The National Conference On Undergraduate Research (NCUR), Eastern Washington University, Cheney, Wash. 


Wolfgang Schweigkofler, Kathleen Kosta, Vernon Huffman, Supriya Sharma, Karen Suslow and Sibdas Ghosh. 2014. Steaming inactivates Phytophthora ramorum, causal agent of sudden oak death and ramorum blight, from infested nursery soils in California. Plant Health Progress doi:10.1094/PHp-RS-13-0111


Wolfgang Schweigkofler, Kathleen Kosta, Vernon Huffman, Tomas Pastalka, Glenn Copeland, Karen Suslow, Aurelio Posadas, Russ Bulluck and Sibdas Ghosh. 2012. Disease Management of Phytophthora ramorum in a Research Quarantine Nursery at NORS-DUC. Phytophthora in Forests and Natural Ecosystems, Proceedings of the 6th Meeting of the International Union of Forest Research Organizations (IUFRO) Working Party S07-02-09, 127-129


Sheila Johnson-Brousseau, Michael Henkes, Kathleen Kosta, Karen Suslow, Aurelio Posadas and Sibdas Ghosh. 2011. Phytophthora ramorum research at the National Ornamentals Research Site at the Dominican University of California. New Zealand Journal of Forestry Science 41S, 101-113