Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Work has been continuing on the characterization of Waitea patch, a new Rhizoctonia disease present in the U.S. on turfgrass. We found that nitrogen is an important component for the control of this disease. We are concluding work on gray leaf spot population diversity and have conclusively shown the differences between ryegrass and kikuyugrass populations in California. Work on rapid blight, an invasive pathogen of turf is being more emphasized in our program. A very active turf fungicide testing program was performed in 2009. Fungicide trials were performed for dollar spot, Waitea patch, algae, southern blight, summer patch and anthracnose.The state-wide disease diagnostic program received over 500 turf and ornamental samples form the western U.S. Events participated in showcased information generated from the activities and included 15 extension or industry education seminars to disseminate the information to the turfgrass and landscape industries. Products included the dissemination of pest management information through handouts and brochures made available at the aforementioned seminars and presentations. Also a website with much of the information is maintained at www.turfpathology.ucr.edu, and electronic information is disseminated to over 450 users in the turf industry via email on a routine basis. PARTICIPANTS: Frank Wong, CE Specialist Juanita Rios, Lab Technician TBD, Staff Research Associate Chi-min Chen, PhD student, expected graduation 2011 Joey Young, MS Student (Mississippi State University), expected graduation 2009 Cooperating Faculty/UC Personnel Greg Douhan, Assistant Professor, Department of Plant Pathology & Microbiology Don Cooksey, Professor, Department of Plant Pathology & Microbiology James Baird, CE Specialist, Department of Botany and Plant Sciences Steve Cockerham, Director, Agricultural Operations Steve Ries, Staff Research Associate, Agricultural Operations Ali Harivandi, Environmental Horticulture Advisor, Alameda County Jim Downer, Environmental Horticulture Advisor, Ventura County Don Hodel, Environmental Horticulture Advisor, Los Angeles County Janet Hartin, Environmental Horticulture Advisor, San Bernardino County Mike Henry, Environmental Horticulture Advisor, Riverside County John Kabashima, Environmental Horticulture Advisor, Orange County Michelle LeStrange, Farm Advisor, Tulare County Institutional Units Involved: UC Statewide Cooperative Extension University of California Statewide Integrated Pest Management Program University of California Turfgrass Working Group University of California Landscape Working Group Cooperation (Non-UC): John Kaminiski, University of Connecticut, Department of Plant Sciences Lane Tredway, North Carolina State University, Department of Plant Pathology Bruce Clarke, Rutgers University, Department of Plant Science and Pathology Brad Hillman, Rutgers University, Department of Plant Science and Pathology Joanne Crouch, Rutgers University, Department of Plant Science and Pathology Tom Hsiang, University of Guelph, Department of Environmental Sciences Pete Landschoot, Pennsylvania State University, Department of Agronomy Wakar Uddin, Pennsylvania State University, Department of Plant Pathology TARGET AUDIENCES: Golf Course Superintendents Associations of America Sports Turf Managers Association United States Golf Association University of California Cooperative Extension Staff University of California Master Gardeners PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Work on Waitea patch has also lead to a understanding of the how the disease has emerged and spread and causes disease. This work has also increased the knowledge of this and related fungi and may cause a reclassification of one genus of fungi that are considered Rhizoctonias. The field trial results from fungicide testing has produced better guidelines for fungicide use patterns for disease control. Finally, the information generated from the disease diagnostic lab has allowed turf managers to make the correct decisions for pest management. We have also used this information to track the spread of various turf diseases and identify that stress and soil borne diseases are of increasing importance in turf management.
Publications
- Chen, C.-M., de la Cerda, K. A., Kaminski, J. E., Douhan, G. W., and Wong, F. P. 2009. Geographic distribution and genetic diversity of Waitea circinata var. circinata isolated from annual bluegrass in the U.S. Plant Disease 93:906-911
- Douhan, G. W., Olsen, M. W., Herrell, A., Winder, C. and Wong, F. P. 2009. Genetic diversity of Labyrinthula terrestris, causal agent of rapid blight disease of turfgrass, a new emergent disease caused by over salinification of the soil and newly discovered Labyrinthulid organisms. Mycological Research 113:1192-1199.
- Hernandez-Martinez, R., Cooksey, D. A. and Wong, F. P. 2009. Two new diseases in Southern California produced by Xylella fastidiosa subspecies multiplex: leaf scorch in purple-leaved plum and sweetgum dieback. Plant Disease (in press)
- Wong, F. P., Chen, C. -M., Stowell, L. J. and Carpenter, W. B. 2009. Evaluation fungicides for the control of brown ring patch in southern California, 2008. Plant Disease Management Reports 3:T009
- Wong, F. P., Chen, C. -M., Stowell, L. J. and Carpenter, W. B. 2009. Evaluation of QoI fungicide mixtures for the control of brown ring patch in southern California, 2008. Plant Disease Management Reports 3:T034
- Wong, F. P., Chen, C. -M., Stowell, L. J. and Carpenter, W. B. 2009. Evaluation of DMI and biological fungicides for the control of brown ring patch in southern California, 2008. Plant Disease Management Reports 3:T008
- Wong, F. P., and Rios, J. C. 2009. Evaluation of fungicides for suppression of algae in southern California, 2007. Plant Disease Management Reports 3:T006
- Wong, F. P., and Rios, J. C. 2009. Evaluation of fungicides mixtures for the control of brown patch on warm season turf in southern California, 2008. Plant Disease Management Reports 3:T001
- Wong, F. P., and Rios, J. C. 2009. Evaluation of Insignia fungicide and surfactants for curative control of southern blight in southern California, 2007. Plant Disease Management Reports 3:T004
- McDonald, S. J., Fidanza, M. A., Wong, F. P., Mysliwiec, T. H. and Averell, R. M. 2009. First report of brown ring patch caused by Waitea circinata var. circinata on Poa annua in Pennsylvania. Plant Disease 9:962.
- Wong, F. P., and Rios, J. C. 2009. Evaluation of fungicides for curative control of dollar spot in southern California, 2008 (II). Plant Disease Management Reports 3:T002
- Wong, F. P., and Rios, J. C. 2009. Evaluation of fungicides for curative control of dollar spot in southern California, 2008 (I). Plant Disease Management Reports 3:T003
- Wong, F. P., and Rios, J. C. 2009. Evaluation of fungicides for curative control of southern blight in southern California, 2007. Plant Disease Management Reports 3:T005
- Wong, F. P., and Rios, J. C. 2009. Evaluation of fungicides for curative control of dollar spot in southern California, 2007. Plant Disease Management Reports 3:T006
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Outputs for this project include the development of a number of extension publications and presentations, and the presentation of findings to members of the scientific community at professional meetings. An important reference material was developed for the general public through the publication of 'Best Management Pratices or Turfgrass Anthracnose' throgh the Golf Course Superintendents Association of America and the Uinted States Golf Association. This disease is one of the most important diseases of turfgrass world wide and the management guidelines provide a valuable reference tool for turfgrass managers in the U.S. The turfgrass disease diagnostic service processed 496 samples for turfgrass managers in the western U.S. The results of these tests provided important information for these managers to make key pest control decisions. Information gained from the diagnostic lab was also disseminated to the California turgrass industry through a weekly electronic bulletin and web-based report. Information obtained from the project was used in 20 extension presentations made to the turfgrass industry and managers. These included presentations through out California, Hawaii, Idaho and Washington, and an international presentation in Morelia, Mexico. Three presentations using data generated from the project were made at the Annual Meeting of the American Phytopathology Society. Two presentations were made at the International Symposium on Rhizoctonia in Berlin, Germany and two invited University seminars were give suing this information. All together, the outputs of this project provided useful disease management information that helps turfgrass managers directly and provided findings that advanced the advancement of disease management and the understanding of plant pathogens in the scientific community. PARTICIPANTS: Greg Douhan, Professor, University of California, Riverside, Department of Plant Pathology Chi Min Chen, Graduate Research Assistant, University of California, Riverside, Department of Plant Pathology (Ph D Thesis Project mentor) Juanita Rios, Staff Research Assistant, University of California, Riverside, Department of Plant Pathology Mary Olsen, Professor, University of Arizona, Department of Plant Pathology Maria Tomaso-Peterson, Professor, Mississppi State University, Department of Entomology & Plant Pathology Joey Young, Graduate Research Assistant, Mississppi State University, Department of Entomology & Plant Pathology (MS Thesis Project mentor) Wakar Uddin, Professor, the Pennsylvania State University, Department of Plant Pathology TARGET AUDIENCES: Turgrass, landcape and ornamental industries in California and western U. S. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Research conducted on Waitea patch resulted several key outcomes and impacts for the turf industry. First, research demonstrated that the disease is widespread in the U.S. and should be considered an invasive or emergent disease of turgrass. Second, experiments were performed to develop best management practices for this disease. We found that nitrogen fertility was a key component in the development of the disease. Low fertility turf was much more severely affected by the disease and in field trials, it was found that increased fertility, regardless of source (nitrate, ammonium or urea) was effective in reducing the impact of the disease.. Finally, we found that only a few fungicides were capable of controlling the disease; these included polyoxin-D, azoxystrobin, propiconazole, metconazole, triticonazole, and flutolanil. All together, the work on this disease has lead to the development of some best management practices for this new disease. Research on Gray Leaf Spot, an emergent disease of turfgrass has shown that populations affecting perennial ryegrass in California are nearly identical to those found in the eastern U.S. using amplified fragment length polymorphism analysis (AFLP). This suggests that pathogen movement in the U. S. on turfgrass is common and that invasive diseases are a real threat to the turfgrass industry. On the other hand, we found that populations affecting kikuyugrass in California are very diverse and have the potential for sexual recombination. This is important as it would be one of a few cases of sexual reproduction in this pathogen in the U.S., potentially generating new races that could affect other grass and cereal crops in the U.S. Work was also completed on Labyrinthula terrestris, another invasive pathogen of turfgrass in the U.S. that attacks plants in salt affected sites. AFLP analyses indicated that the pathogen population is diverse and suggests that the emergence of the disease is due to changes in soil salinity rather than pathogen invasion. Since these pathogens affect plants in saline conditions, we are focusing on the biology of this pathogen and its ability to attack other crops of economic importance including food, fuel and fiber crops. Turfgrass anthracnose work was performed with scientists at Mississippi State University to characterize QoI and benzimidazole fungicide resistance for this pathogen in the southeastern U.S. They found that resistance to both is present in several locations and described a novel mutation in the pathogen conferring benzimidazole resistance. This suggests that fungicide resistance development in this pathogen can develop independently in different location through different molecular mechanisms. Results from the project for the insect vectored bacterial scorch pathogen, Xylella fastidiosa, confirmed that two new diseases of sweetgum (liquidambar) and ornamental plum are caused by strains of the bacteria related to those that cause almond leaf scorch. New scorch disease symptoms were detected in diverse hosts in southern California including redwood. It appears that new strains of this pathogen require further characterization.
Publications
- Chen, C. M., and Wong, F. P. 2008. In vitro sensitivity of Waitea circinata var. circinata to fludioxonil and polyoxin-D. Phytopathology 98:S37
- Chen, C. M., Douhan, G. W., and Wong, F. P. Characterization and genome diversity of Waitea circinata var. circinata, an emerging pathogen on turfgrass. Proceedings of the 4th International Symposium on Rhizoctonia. August 20-22, 2008, Berlin, Germany. Page 7.
- de la Cerda, K. A., Chen C., Kaminski, J. E., Douhan, G. W., and Wong, F. P. 2009. Geographic distribution and genetic diversity of Waitea circinata var. circinata isolated from annual bluegrass in the U.S. Plant Disease XX:XX (in press)
- Hernandez-Martinez, R., Cooksey, D. A. and Wong, F. P. 2008. Two new diseases in Southern California produced by Xylella fastidiosa subspecies multiplex: leaf scorch in purple-leaved plum and sweet gum dieback. Plant Disease XX:XX (in press)
- Kern, J., Uddin, W., Wong, F. 2008. The effects of temperature and leaf wetness duration on the development of gray leaf spot in kikuyugrass turf. Phytopathology 98:S80
- McDonald, S. J., Fidanza, M. A., Wong, F. P., Mysliwiec, T. H. and Averell, R. M. 2008. First report of brown ring patch caused by Waitea circinata var. circinata on Poa annua in Pennsylvania. Plant Disease (in press)
- Murphy, J., Wong, F., Tredway, L., Crouch, J., Inguagiato, J., Clarke, B., Hsiang, T., and Rossi, F. 2008. Best management practices for anthracnose on annual bluegrass turf. Golf Course Management 76(8):93-104.
- Murphy, J., Wong, F., Tredway, L., Crouch, J., Inguagiato, J., Clarke, B., Hsiang, T., and Rossi, F. 2008. Best management practices for anthracnose on annual bluegrass turf. USGATurfgrass and Environmental Research Online 7(16):1-16.
- Urak, R. Z, Douhan, G. W., and Wong F. 2008. Mating-type distribution of the rice blast pathogen Pyricularia grisea in California. UCR Undergraduate Research Journal 2:61-65.
- Wong, F. P., de la Cerda, K. A., Chen, C. M., Douhan, G. W., Takeshi, T., Kaminski, J. E., Harmon, P. F., and Tredway, L. P. The Biology and Management of Rhizoctonia in Turf. Proceedings of the 4th International Symposium on Rhizoctonia. August 20-22, 2008, Berlin, Germany. Page 35.
- Young, J. R., Peterson, M. T., Wong, F. P. and de la Cerda, K. 2008. Thiophanate methyl-resistant Colletotrichum cereale isolates exhibiting amino acid substitutions in the beta-tubulin 2 gene. Phytopathology 98:S178
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: For this reporting period, activities focused mainly on the biology and control of fungal diseases. Anthracnose remains a high concern for our program, but research was reduced in this area due to other emerging diseases. However, Joey Young, a MS student from Mississippi State University under my direction did successfully determine and characterize the presence of both QoI and benzimidazole resistance in C. cereale populations from the southern U.S. For gray leaf spot, California populations from turfgrass were successfully characterized using amplified fragment length polymorphism (AFLP) analysis, showing that populations from kikuyugrass are distinct from those causing the disease on perennial ryegrass and tall fescue. The disease was also found on tall fescue for the first time in California in 2007. Two mating types were identified in kikuyugrass populations which is unique in the U.S. Populations of the pathogen from rice were also collected and characterized by AFLP.
Work has been continuing on the characterization of Waitea patch, a new Rhizoctonia disease present in the U.S. on turfgrass. Molecular analysis of ribosomal DNA sequences has identified this pathogen as being identical to pathogens of bentgrass in Japan and wheat in Washington. The disease was also detected in the midwest and northeastern U.S., indicating it is widespread as a pathogen.A very active turf fungicide testing program was performed in 2007. Fungicide trials were performed for dollar spot, Waitea patch, algae, southern blight, summer patch and anthracnose. Pythium seedling damping off trials were not conducted in the field but could be performed in the greenhouse. Herbicidal control of annual bluegrass studies were also undertaken in 2007. The state-wide disease diagnostic program received over 400 turf and ornamental samples form the western U.S. No research activities were conducted on Xylella diseases of landscape ornamentals or Fusarium wilt of palm trees. Events
participated in showcased information generated from the activities and included 6 scientific presentations at the American Phytopathology Society Annual Meeting, 1 at the California Invasive Plant Council Annual Meeting, and 1 Mississippi Association of Plant Pathologist and Nematologist Meeting. One workshop was given at the Golf Course Superintendents Association of America Annual Conference and six seminars were given at academic institutions. Information from this project was also presented at 21 extension or industry education seminars to disseminate the information to the turfgrass and landscape industries. Products included the dissemination of pest management information through handouts and brochures made available at the aforementioned seminars and presentations. Also a website with much of the information is maintained at www.turfpathology.ucr.edu, and electronic information is disseminated to over 450 users in the turf industry via email on a routine basis.
PARTICIPANTS: Frank Wong, CE Specialist Juanita Rios, Lab Technician TBD, Staff Research Associate Chi-min Chen, PhD student, expected graduation 2011 Joey Young, MS Student (Mississippi State University), expected graduation 2009 Cooperating Faculty/UC Personnel Greg Douhan, Assistant Professor, Department of Plant Pathology & Microbiology Don Cooksey, Professor, Department of Plant Pathology & Microbiology James Baird, CE Specialist, Department of Botany and Plant Sciences Steve Cockerham, Director, Agricultural Operations Steve Ries, Staff Research Associate, Agricultural Operations Ali Harivandi, Environmental Horticulture Advisor, Alameda County Jim Downer, Environmental Horticulture Advisor, Ventura County Don Hodel, Environmental Horticulture Advisor, Los Angeles County Janet Hartin, Environmental Horticulture Advisor, San Bernardino County Mike Henry, Environmental Horticulture Advisor, Riverside County John Kabashima, Environmental Horticulture Advisor, Orange County
Michelle LeStrange, Farm Advisor, Tulare County Institutional Units Involved: UC Statewide Cooperative Extension University of California Statewide Integrated Pest Management Program University of California Turfgrass Working Group University of California Landscape Working Group Cooperation (Non-UC): John Kaminiski, University of Connecticut, Department of Plant Sciences Lane Tredway, North Carolina State University, Department of Plant Pathology Bruce Clarke, Rutgers University, Department of Plant Science and Pathology Brad Hillman, Rutgers University, Department of Plant Science and Pathology Joanne Crouch, Rutgers University, Department of Plant Science and Pathology Tom Hsiang, University of Guelph, Department of Environmental Sciences Pete Landschoot, Pennsylvania State University, Department of Agronomy Wakar Uddin, Pennsylvania State University, Department of Plant Pathology
PROJECT MODIFICATIONS: Developing management strategies for Waitea Patch (Waitea circinata var circinata) Waitea patch is a new disease of turfgrass in the U.S. that was first found in the western U.S. and now appears to be widespread in the U.S. We are using molecular methods (AFLP, ITS and beta tubulin sequence) to examine population structure to determine the origin and mechanism of spread of the disease. Environmental factors contributing to the development of the disease are being determined. We are also examining the effect of fungicide spray programs and cultural practices on the control and management of the disease.
Impacts
Anthracnose research has resulted in an increased awareness of fungicide resistance issues in the southern U.S., resulting in a change in management practices to reduce those that increase fungicide resistance development. These include a focus on less reliance for pesticidal control of the pathogen and a focus on cultural practices. Research on Gray Leaf Spot has lead to an understanding of how the disease emerged in the western U.S. and how it can spread and cause disease. A better understanding of the host-pathogen relationship has allowed for turf managers to choose more tolerant varieties or species to grow. The discovery of the two mating types of the pathogen on kikuyugrass also has changed the knowledge base as this is the first sexual population of the pathogen to be found in the western U.S. Work on Waitea patch has also lead to a similar understanding of the how the disease has emerged and spread and causes disease. This work has also increased the knowledge
of this and related fungi and may cause a reclassification of one genus of fungi that are considered Rhizoctonias. The field trial results from fungicide testing has produced better guidelines for fungicide use patterns for disease control. These included changing the way that algae is managed and the importance of application techniques for the control of soil borne diseases. Finally, the information generated from the disease diagnostic lab has allowed turf managers to make the correct decisions for pest management. We have also used this information to track the spread of various turf diseases and identify that stress and soil borne diseases are of increasing importance in turf management.
Publications
- Chen, C. M. and Wong, F. P. 2007. First report of Waitea circinata var. circinata on Poa trivialis in the United States. Plant Disease 12:1687.
- Chen, C., de la Cerda, K. A., Kaminski, J. E., Douhan, G. W., and Wong, F. P. 2007. Geographic distribution and genetic diversity of Waitea circinata var. circinata isolated from annual bluegrass in the U.S. Phytopathology 97:S21
- de la Cerda, K. A., Douhan, G. W., and Wong, F. P. 2007. Discovery and Characterization of Waitea circinata var. circinata affecting Annual Bluegrass from the western United States. Plant Disease 91:791-797.
- de la Cerda, K. A., Huryn, K. L., Douhan, G. W., and Wong, F. P. 2007. Mating-type distribution of Pyricularia grisea associated with turfgrass in California. Phytopathology 97:S26
- Fidanza, M. A., Wong, F. P., Kostka, S. J, and McDonald, S. J. 2007. Use of a Soil Surfactant with Fungicides for Control of Fairy Ring Disease in Turfgrass Journal of ASTM International, Vol. 4, No. 4, ID:JAI100892 (6 pages)
- Fidanza, M. A., Wong, F. P., Martin, S. B., and McDonald, S. J. 2007. Treating fairy ring with fungicides, new soil surfactant. Golf Course Management 75(5):121-125.
- Hernandez-Martinez, R., de la Cerda, K. A., Costa, H. S., Cooksey, D. A., and Wong, F. P. 2007. Phylogenetic relationships of Xylella fastidiosa strains isolated from ornamentals in southern California. Phytopathology 97:857-864.
- Kaminski, J. E. and Wong, F. P. 2007. Brown Ring Patch. University of Connecticut Turfgrass Disease Bulletin.
- Kern, J. J., Uddin, W. and Wong, F. P. 2007. Cross-infectivity of Magnaporthe oryzae isolates causing gray leaf spot in perennial ryegrass and kikuyugrass truf. Phytopathology 97:S56
- Wong, F. P. , and Rios, J. C. Evaluation of fungicides for the control of gray leaf spot on perennial ryegrass in southern California 2005. Plant Disease Management Reports 1:T061.
- Wong, F. P. , Rios, J. C., Ries, S. B. 2007. Evaluation of fungicides for the control of fairy ring and localized dry spot in southern California, 2005. Plant Disease Management Reports 1:T058
- Wong, F. P. , Rios, J. C., Ries, S. B. 2007. Evaluation of fungicides for the control of fairy ring and localized dry spot in southern California, 2006. Plant Disease Management Reports 1:T057
- Wong, F. P. , Rios, J. C., Ries, S. B. 2007. Evaluation of fungicides for the control of dollar spot in southern California, 2005. Plant Disease Management Reports 1:T059
- Wong, F. P. , Rios, J. C., Ries, S. B. 2007. Evaluation of fungicides for the control of anthracnose in southern California, 2006. Plant Disease Management Reports 1:T063.
- Wong, F. P. , Rios, J. C., Ries, S. B. 2007. Evaluation of fungicides for the control of anthracnose in southern California, 2005. Plant Disease Management Reports 1:T064.
- Wong, F. P. and Kaminski, J. E. 2007. Wcc: A yellow patch imposter. Bayer Golf Advantage 4(1):33-34.
- Wong, F. P. and Kaminski, J. E. 2007. Waitea circinata var circinata: a new pathogen of bluegrass greens. Golf Course Management 75(9):98-103.
- Wong, F. P. and Stowell, L. 2007. Evaluation of fungicides for the curative control of brown ring patch in southern California, Spring 2006. Plant Disease Management Reports 1:T062.
- Wong, F. P., and Midland, S. L. 2007. Sensitivity distributions of California populations of Colletotrichum cereale to four sterol demethylation inhibitor fungicides: propiconazole, myclobutanil, tebuconazole and triadimefon. Plant Disease 91:1547-1555
- Wong, F. P., de la Cerda, K. A., Hernandez-Martinez, R., and Midland, S. L. 2007. Detection and characterization of benzimidazole resistance in California populations of Colletotrichum cereale. Plant Disease 92:239-246
- Wong, F. P., de la Cerda, K., and Ries, S. B. 2007. Evaluation of fungicides for the control of dollar spot in southern California, 2005. Plant Disease Management Reports 1:T060.
- Wong, F. P., Midland, S. L. and de la Cerda, K. A. 2007. Occurrence and distribution of QoI-resistant isolates of Colletotrichum cereale from annual bluegrass in California. Plant Disease 91:1536-1546.
- Young, J., Tomaso-Peterson, M., and Wong, F. 2007. Screening for azoxystrobin-resistant Colletotrichum cereale isolates of the Mid-South. Phytopathology 97:S128
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Progress 01/01/05 to 12/31/05
Outputs
(1) Developing management strategies for Turfgrass Anthracnose (C. cereale) We have been focusing the work on three aspects of C. cereale (ex. C. graminicola)(i) differential responses to sterol biosynthesis inhibitor (SI-) fungicides,(ii) sensitivity to fludioxonil and (iii) field testing of fungicides. We have found that in testing baseline and reduced-sensitivity populations that isolates of C. cereale were most sensitive to tebuconazole, followed by propiconazole, myclobutanil and triadimefon. This shows that for practical control of this disease that fungicides with the highest activity should be used for its control in the field. Fludioxonil is a phenylpyrrole fungicide recently labeled for the control of C. cereale; and is at risk for resistance development. To develop methods to resistance development, a baseline sensitivity distribution was determined; ED50 values for 60 baseline isolates ranged from 0.0010 to 2.5 mg/L with mean of 0.60 mg/L. The impact of
the isolates with increased ED50 value is being investigated at this time. Since there is a high prevalence of QoI, benzimidazole and SI-resistance in C. cereale populations, the efficacy of alternative fungicide treatments was investigated in the field. It was found that preventive applications of chlorothalonil, fludioxonil, polyoxin-D and tank mixes with fosetyl-Al were good alternative treatments. (2) Developing management strategies for Grey Leaf Spot (P. grisea) on Perennial Ryegrass and Kikuyugrass in California A survey to detect QoI resistance in populations of P. grisea indicated both F129L tolerant isolates and G143A immune isolates were found in California populations. The population structure of P. grisea was analyzed using amplified fragment length polymorphisms (AFLP) and specific amplification of mating type genes. Initial results indicate that this pathogen is not a recent introduction to California and that Kikuyugrass isolates may be closely related to crabgrass
isolates and may be sexually reproducing. (3) Evaluation and characterization of fungicides for turfgrass disease management In 2005, fungicide performance was evaluated against C. cereale, Rhizoctonia cerealis, Sclerotinia homoeocarpa, Michrodochium nivale, Sclerotium rolfsii and basidiomycetes causing fairy ring on turf. (4) Establishment of a state-wide diagnostic center for turfgrass disease diagnosis Over 350 samples were diagnosed from California, Washington, Nevada, Colorado and Oregon. From the samples, it was determined that a species of Waitea circinata was causing disease in golf course putting greens that had not been previously described in the U.S.. (5) Detection and characterization of X. fastidiosa strains from landscape hosts In 2005, it was shown that X. fastidiosa was the causal agent of disease in Mulberry, Sweetgum and ornamental plum. Characterization of these isolates showed that those affecting sweetgum and plum were subspecies multiplex. Strains affecting
mulberry were almost 100% identical to strains previously described in the eastern U.S. (6) Development of management strategies for the control of Fusarium Wilt of Palm No research was performed in this area this past year.
Impacts
The impact of our project is providing new information to help reduce the impact of diseases of turf and landscape on the California green industry with regard to the economic cost of pest management and the aesthetic impact of these diseases. The research conducted this year has provided key insights on the biology and control of two diseases directly impacting the multi-billion dollar California golf course industry. Fungicide testing results have given the industry unbiased information regarding best control options and recommendations. Also the state wide turf disease diagnostic laboratory has provided turf managers timely and important information with regard to the correct identification of their problems, and identified a new disease affecting turf in the western U.S. Finally, our research has proved the role of X. fastidiosa in causing new diseases of landscape plants, indicating that the presence of this bacteria in California is not only a threat to
agricultural crops but also to urban landscapes
Publications
- McCullough, M. D., and Wong, F. P.. 2005. Evaluation of mid-season fungicide applications for the control of anthracnose on a mixed annual bluegrass and creeping bentgrass green in northern California, summer 2004. Report 60:T056. APS Fungicide and Nematicide Tests 60 (online) Wong, F. P., and Rios, J. C.. 2005. Control of summer patch and anthracnose on an annual bluegrass green in southern California, 2004. Report 60:T058. APS Fungicide and Nematicide Tests 60 (online) Wong, F. P. and. de la Cerda, K. A. 2006. First Report of Pyricularia grisea (Gray Leaf Spot) on Perennial Ryegrass (Lolium perenne) in Nevada. Plant Disease 90 (accepted December 2005) Wong, F. P., de la Cerda, K., and Ries, S. B.. 2005. Evaluation of fungicides for the control of dollar spot in southern California, spring 2004. Report 60:T057. APS Fungicide and Nematicide Tests 60 (online) Wong, F. P., de la Cerda, K. A., Midland, S. L., and Hernandez-Martinez, R 2005. Benzimidazole resistance in
California isolates of Colletotri
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