Kathleen Kosta - Academia.edu (original) (raw)

Papers by Kathleen Kosta

Research paper thumbnail of Sunflower Diseases Remain Rare in California Seed Production Fields Compared to North Dakota

Plant Health Progress, 2012

The majority of United States sunflower production is in seven Midwestern states, but hybrid plan... more The majority of United States sunflower production is in seven Midwestern states, but hybrid planting seed is almost exclusively produced in California. Due to the lack of summer rains and furrow irrigation, California-produced seed is relatively disease free and thus it regularly meets phytosanitary restrictions imposed by many countries. For the 15-year period from 1997 to 2011, 7231 seed fields in northern California were inspected and samples processed at the state diagnostic laboratory (California Department of Food and Agriculture). Rust (Puccinia helianthi) was the most prevalent quarantine disease, found in 4.3% of fields. Stalk rot (Sclerotinia sclerotiorum) and downy mildew (Plasmopara halstedii) were the only other quarantine pathogens observed, found in 2.6% and 0.5% of the 7231 fields, respectively. Many sunflower pathogens have never been recorded in California, including Phoma macdonaldii, Phomopsis helianthi, or any virus. North Dakota, the state with the highest US sunflower production, had quarantine pathogens in 88% of 1263 fields surveyed from 1995 to 2011. Phoma macdonaldii, Sclerotinia sclerotiorum, Puccinia helianthi, Phomopsis helianthi, Plasmopara halstedii, and Verticillium dahliae were recorded in 62

Research paper thumbnail of Research on the Quarantine Pathogen Phytophthora ramorum at the National Ornamentals Research Site at Dominican University of California (NORS-DUC)

ABSTRACT Phytophthora ramorum, the causal agent of Sudden Oak Death and Ramorum blight, can infes... more ABSTRACT Phytophthora ramorum, the causal agent of Sudden Oak Death and Ramorum blight, can infest several dozen host plants, among them many important ornamental plants like Rhododendron, Viburnum and Camellia. Federal and state regulations require the destruction of nursery plants infected by P. ramorum and treatment of contaminated soil. Infected nursery material is also a possible factor in the long-range spread of P. ramorum. The National Ornamentals Research Site at Dominican University of California (NORS-DUC) was founded in the year 2009 by a Farm Bill grant to study P. ramorum in a sophisticated research nursery that reflects an authentic commercial nursery setting (www.dominican.edu/norsduc). NORS-DUC goals are to develop practical solutions for containment, remediation, and eradication of quarantine pathogens in nurseries, reducing the risk of long-range spread of pests through infested nursery stock shipments. Research at NORS-DUC is conducted by a team of permanent staff as well as by P. ramorum experts from other institutions who can apply for grants to work at NORS-DUC. The research site offers a unique opportunity to study different aspects of P. ramorum diseases of ornamentals that has not been accomplished previously. First results from research on the eradication of P. ramorum from soils using steam sterilization, solarization and bio-control using a new Trichoderma isolate indicate they were effective; and these methods are being reviewed by USDA APHIS as approved for soil treatments in infected commercial nurseries. Ongoing research is focusing on the disease epidemiology in nurseries, the genetic plasticity of P. ramorum on different host plants and the effects of fungicides and physiological stress on symptom development.

Research paper thumbnail of Steaming Inactivates Phytophthora ramorum, Causal Agent of Sudden Oak Death and Ramorum Blight, from Infested Nursery Soils in California

Plant Health Progress, 2014

Research paper thumbnail of Disease management of Phytophthora ramorum in a reserach quarantine nursery at NORS-DUC

Sudden Oak Death, caused by Phytophthora ramorum Werres, De Cock & Man in`t Veld, is among the mo... more Sudden Oak Death, caused by Phytophthora ramorum Werres, De Cock & Man in`t Veld, is among the most important emerging forest diseases with potentially devastating effects on temperate forests. The nursery trade is a factor in the long-range spread of P. ramorum. To address threats posed by plant trade and aid in developing an environmentally-sustainable nursery industry, the National Ornamentals Research Site at Dominican University of California (NORS-DUC) was developed (www.dominican.edu/norsduc). NORS-DUC is a sophisticated field nursery designed to contain quarantined pathogens for the purpose of conducting research in a safe environment that reflects an authentic nursery setting. Research currently focuses on P. ramorum and is conducted by a consortium of P. ramorum experts. NORS-DUC offers an unparalleled opportunity to study the epidemiology of P. ramorum diseases of ornamentals that has not been accomplished previously. First results from research on the disinfection of P. ...

Research paper thumbnail of Sunflower Diseases Remain Rare in California Seed Production Fields Compared to North Dakota

Plant Health Progress, 2012

The majority of United States sunflower production is in seven Midwestern states, but hybrid plan... more The majority of United States sunflower production is in seven Midwestern states, but hybrid planting seed is almost exclusively produced in California. Due to the lack of summer rains and furrow irrigation, California-produced seed is relatively disease free and thus it regularly meets phytosanitary restrictions imposed by many countries. For the 15-year period from 1997 to 2011, 7231 seed fields in northern California were inspected and samples processed at the state diagnostic laboratory (California Department of Food and Agriculture). Rust (Puccinia helianthi) was the most prevalent quarantine disease, found in 4.3% of fields. Stalk rot (Sclerotinia sclerotiorum) and downy mildew (Plasmopara halstedii) were the only other quarantine pathogens observed, found in 2.6% and 0.5% of the 7231 fields, respectively. Many sunflower pathogens have never been recorded in California, including Phoma macdonaldii, Phomopsis helianthi, or any virus. North Dakota, the state with the highest US sunflower production, had quarantine pathogens in 88% of 1263 fields surveyed from 1995 to 2011. Phoma macdonaldii, Sclerotinia sclerotiorum, Puccinia helianthi, Phomopsis helianthi, Plasmopara halstedii, and Verticillium dahliae were recorded in 62

Research paper thumbnail of Research on the Quarantine Pathogen Phytophthora ramorum at the National Ornamentals Research Site at Dominican University of California (NORS-DUC)

ABSTRACT Phytophthora ramorum, the causal agent of Sudden Oak Death and Ramorum blight, can infes... more ABSTRACT Phytophthora ramorum, the causal agent of Sudden Oak Death and Ramorum blight, can infest several dozen host plants, among them many important ornamental plants like Rhododendron, Viburnum and Camellia. Federal and state regulations require the destruction of nursery plants infected by P. ramorum and treatment of contaminated soil. Infected nursery material is also a possible factor in the long-range spread of P. ramorum. The National Ornamentals Research Site at Dominican University of California (NORS-DUC) was founded in the year 2009 by a Farm Bill grant to study P. ramorum in a sophisticated research nursery that reflects an authentic commercial nursery setting (www.dominican.edu/norsduc). NORS-DUC goals are to develop practical solutions for containment, remediation, and eradication of quarantine pathogens in nurseries, reducing the risk of long-range spread of pests through infested nursery stock shipments. Research at NORS-DUC is conducted by a team of permanent staff as well as by P. ramorum experts from other institutions who can apply for grants to work at NORS-DUC. The research site offers a unique opportunity to study different aspects of P. ramorum diseases of ornamentals that has not been accomplished previously. First results from research on the eradication of P. ramorum from soils using steam sterilization, solarization and bio-control using a new Trichoderma isolate indicate they were effective; and these methods are being reviewed by USDA APHIS as approved for soil treatments in infected commercial nurseries. Ongoing research is focusing on the disease epidemiology in nurseries, the genetic plasticity of P. ramorum on different host plants and the effects of fungicides and physiological stress on symptom development.

Research paper thumbnail of Steaming Inactivates Phytophthora ramorum, Causal Agent of Sudden Oak Death and Ramorum Blight, from Infested Nursery Soils in California

Plant Health Progress, 2014

Research paper thumbnail of Disease management of Phytophthora ramorum in a reserach quarantine nursery at NORS-DUC

Sudden Oak Death, caused by Phytophthora ramorum Werres, De Cock & Man in`t Veld, is among the mo... more Sudden Oak Death, caused by Phytophthora ramorum Werres, De Cock & Man in`t Veld, is among the most important emerging forest diseases with potentially devastating effects on temperate forests. The nursery trade is a factor in the long-range spread of P. ramorum. To address threats posed by plant trade and aid in developing an environmentally-sustainable nursery industry, the National Ornamentals Research Site at Dominican University of California (NORS-DUC) was developed (www.dominican.edu/norsduc). NORS-DUC is a sophisticated field nursery designed to contain quarantined pathogens for the purpose of conducting research in a safe environment that reflects an authentic nursery setting. Research currently focuses on P. ramorum and is conducted by a consortium of P. ramorum experts. NORS-DUC offers an unparalleled opportunity to study the epidemiology of P. ramorum diseases of ornamentals that has not been accomplished previously. First results from research on the disinfection of P. ...