PARENT SESSION
Oral Session #48: Spatial patterns, spatial processes. Presiding: D. Deutschman.
Wednesday, August 8, 2001. 1:00 PM to 5:00 PM. Madison Ballroom C.
Spatial dynamics of dogwood anthracnose in the eastern United States.
Russell, Colin1,3, Lucey, Brendan1,3, Waller, Lance2,3, Childs, James3,4, Real, Leslie1,3, 1 3 2 4
ABSTRACT- Dogwood anthracnose poses a potentially lethal threat to Cornus florida populations in the eastern United States. Since its initial outbreak in the northeastern US, dogwood anthracnose has spread southward now occurring in 20 states along the eastern seaboard. We analyzed US Forest Service records of the year of first appearance of this disease in 240 counties within the southeastern US. We used Point Kriging and Trend Surface Analysis to statistically characterize the structure of epidemic spread. Vector field analysis of the pattern of spread indicates a statistically significant association between high elevation and the high rates of local propagation. Approximately 14% of the variation in local rates of propagation is attributable to variation in elevation (df = 244, p<.0001). The correlation between disease incidence and elevation has been suggested in the literature. However, this is the first quantitative assessment of the variation in the velocity of epidemic spread and an important environmental variable. The data also indicate that propagation may be more rapid than initially suspected. Spatial interpolation suggests that the disease may be occurring in areas that are currently not reporting infection. Spatial interpolation can be used as a powerful tool to guide appropriate surveillance strategies.
KEY WORDS: Cornus florida, kriging, elevation