Education
Ph.D. in Plant Pathology (1999), The Ohio State University, Wooster
M.S. in Plant Pathology (1995), University of Georgia, Athens
B.S. in Biology (1992), State University of New York, New Paltz
Division of Effort
Extension - 60%, Diseases of tree fruit and berry crops
Research - 40%, Diseases of tree fruit and berry crops
Research Projects
On Apples. Fire blight, caused by the bacterium Erwinia amylovora, is one of the most destructive and difficult-to-control diseases of apple. The ability to predict the onset of fire blight has been the most limiting factor in improving the overall management of the disease. MARYBLYT is a computer program for forecasting fire blight and the appearance of symptoms that follow. The forecaster has been widely used throughout the world and its performance has received mixed reviews. We propose to: 1) Revise MARYBLYT to calculate a system of "risk points" as a function of the MARYBLYT risk factors, then using the revisions, evaluate various management-action thresholds based on the accumulation of "risk points"; 2) Modify MARYBLYT to account for varietal susceptibility, orchard age, and inoculum potential; and 3) Develop a user-friendly, windows-based version of MARYBLYT. The modifications will incorporate flexibility into MARYBLYT allowing users to choose suitable action thresholds based on variety, orchard age, inoculum pressure, and their comfort for assuming risk. Ultimately, these changes will reduce the cost of managing fire blight by emphasizing efficient, and minimizing unnecessary, applications of antibiotics.
On Stone Fruit. Bacterial canker, caused by the bacteria Pseudomonas syringae pv. syringae and P. s. pv. morsprunorum, is a limiting factor to the production of sweet cherry in New York. The pathogens are known to reside in the vascular tissue. Thus, it is not so simple to ascertain whether diseased trees were infected during propagation or in the field. This uncertainty complicates disease management because control recommendations are built upon the assumption that infection occurs in the field. If infection occurs during propagation then control measures need to target infection during this process. Research will be conducted to first determine baseline levels of epiphytic and systemic populations of P. s. pv. syringae and P. s. pv. morsprunorum on sweet and tart cherry budsticks. Next, we will evaluate the potential of hot-water dips for eradicating or reducing Pseudomonas sp. on sweet and tart cherry budsticks, and then evaluate the effectiveness of a hot water treatment on reducing the rate of bacterial canker development in an orchard environment.
On Strawberry. Leaf spot (Mycosphaerella fragariae), leaf blight (Phomopsis obscurans), and leaf scorch (Diplocarpon earlianum) are foliar diseases of strawberry that can cause significant damage to perennial plantings throughout North America. In a typical year, disease severity reaches its peak at or after harvest on June-bearing varieties. The extent of direct losses attributable to these diseases is not known. However, high levels of disease are responsible for weakening the plant and may dramatically affect the winter hardiness of the plant and, presumably, yield in the following season. Furthermore, it is unclear what effect recurring annual epidemics have on the life span of a perennial planting. Many growers are reluctant to apply fungicides to control foliar diseases after harvest because the economic benefits of doing so are unclear. To assess the value of summer management of foliar diseases, the relationship among foliar disease severity, crop damage, and yield loss will be characterized so that economic thresholds can be developed. The use of an economic threshold as a decision aid for disease management assures that fungicides are applied only when economically feasible.
Curriculum Vitae (PDF)
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