RESEARCH
OBJECTIVES
Advance knowledge of pathogens, environment, and their interaction with hosts
Develop and improve disease management tools
Advance knowledge of pathogens, environment, and their interaction with hosts
Develop and improve disease management tools
Pathogen Biology and Ecology
LETTUCE | Fitness of Verticillium dahliae
Verticillium dahliae Race 2 is a serious threat to lettuce production in Coastal California. However, Race 2 isolates have not been detected on lettuce in the Salinas Valley despite the proximity of Pajaro Valley where Race 2 exists. This project is investigating the fitness of Race 1 and Race 2 V. dahliae strains to understand why Race 2 has not yet become established in the Salinas Valley. Findings from this research could be applied to attempt to preempt this establishment and also to manage Verticillium wilt caused by Race 2 where it is already present. Collaborator: Krishna Subbarao (UC Davis, Salinas) Funded By: California Leafy Greens Research Program |
Disease Epidemiology
ONION | Evaluation of downy mildew weather models
Downy mildew (Peronospora destructor) has the potential to cause severe damage to onion crops in the Imperial Valley of California. Because the environmental conditions required for disease development are complex, however, epidemics are often unpredictable and therefore challenging to manage. This project evaluates the utility of five weather-based models for advising fungicide applications targeting downy mildew of onion in the low desert of California. Collaborator: Jairo Diaz (UC Agriculture and Natural Resources, Holtville) Funded By: California Garlic and Onion Research Advisory Board |
SPINACH | Risk assessment and early detection of downy mildew
Downy mildew (Peronospora effusa) is the most economically important diseases of spinach in California. The detection of P. effusa oospores on seed and on plants originating from infested seed raises questions about the dissemination and evolution of the pathogen. This project is investigating the role that oospores play in downy mildew epidemics in commercial fields. Collaborators: Steve Klosterman (Project Lead - USDA-ARS, Salinas), Krishna Subbarao (UC Davis, Salinas) Funded By: California Leafy Greens Research Program |
STRAWBERRY | Next-generation disease management solutions
The pathogens Colletotrichum acutatum, Fusarium oxysporum f. sp. fragariae, Macrophomina phaseolina, Phytophthora spp., and Verticillium dahliae have emerged or re-emerged as serious threats to strawberry production throughout California. This project will employ advanced methods to detect pathogens and develop tactics to mitigate their movement. We will also be exploring fundamental facets of Macrophomina crown rot, especially the role that abiotic stress plays in the disease. Collaborators: Steve Knapp (Project Lead), Julia Harshman, and Thomas Poorten (UC Davis); Oleg Daugovish (UC Cooperative Extension); Rachael Goodhue and Tom Gordon (UC Davis); Julie Guthman (UC Santa Cruz); Gerald Holmes and Kelly Ivors (Cal Poly San Luis Obispo); Seonghee Lee, Natália Peres, and Vance Whitaker (Univ. of Florida) Funded By: USDA-NIFA Specialty Crops Research Initiative |
RASPBERRY | Management of cane Botrytis
Botrytis cinerea is a pathogen of raspberry that causes a disease of canes that can persist across the multi-year raspberry production system in California. Conditions that are common in California production and likely favor the disease include dense plantings and growth in high tunnels. This project is investigating cultural management of cane Botrytis of raspberry. Collaborators: Driscoll's |
Cropping Systems and Soil Health
TOMATO | Management of Southern blight
Southern blight (Athelia rolfsii) is an aggressive and ubiquitous pathogen that causes severe damage to numerous crops such as processing tomato in the summer heat of California's Central Valley. However, options to manage this disease are limited. Grafting scions of commercial cultivars on to resistant rootstocks has been shown to reduce severity of several diseases of fresh market tomato, but has not been tried in processing tomato. This project aims to evaluate this and other practices to manage Southern blight of processing tomato in California. Collaborators: Joe Nunez (UC Cooperative Extension, Bakersfield), Cassandra Swett (UC Davis) |
Host Resistance and Pathogenicity
STRAWBERRY | Next-generation disease resistance breeding
Macrophomina crown rot (Macrophomina phaseolina) and Anthracnose crown rot (Colletotrichum acutatum) are reemerging in importance for California Strawberry production. We are supporting efforts by the UC Davis Strawberry Breeding Program to identify resistance to these diseases among a diverse set of 960 germplasm accessions in genome-wide association studies. Collaborators: Steve Knapp (Project Lead), Julia Harshman, and Thomas Poorten (UC Davis); Oleg Daugovish (UC Cooperative Extension); Rachael Goodhue and Tom Gordon (UC Davis); Julie Guthman (UC Santa Cruz); Gerald Holmes and Kelly Ivors (Cal Poly San Luis Obispo); Seonghee Lee, Natália Peres, and Vance Whitaker (Univ. of Florida) Funded By: USDA-NIFA Specialty Crops Research Initiative |
Precision Agriculture
STRAWBERRY | Site-specific management of soilborne diseases
The soilborne pathogens Fusarium oxysporum f. sp. fragariae, Macrophomina phaseolina, Phytophthora spp., and Verticillium dahliae have emerged or re-emerged as serious threats to strawberry production throughout California with the phase-out of methyl bromide. This project is developing a zone-based precision fumigation system in which the amount of fumigant to be applied is proportional to the density of soilborne pathogens within that zone. A combination of field scouting, yield, and remote sensing data will evaluate treatment effectiveness and be used to make management decisions for the following crop season. By accounting for the typically uneven spatial distribution of soil pathogens, methods developed in this research could maintain disease management efficacy while reducing overall fumigant use. Collaborators: Frank Martin (USDA-ARS, Salinas), Andre Biscaro and Oleg Daugovish (UC Cooperative Extension, Ventura), Steve Fennimore (UC Davis, Salinas), Rachael Goodhue (UC Davis) Funded By: California Department of Pesticide Regulation |