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United States Department of Agriculture

Agricultural Research Service

Title: Relative Susceptibility of Peach Cultivars to Fungal Gummosis (Botryosphaeria Dothidea)

Authors
item Beckman, Thomas
item Reilly, Charles

Submitted to: Journal of American Pomological Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 2, 2004
Publication Date: April 1, 2005
Citation: Beckman, T.G., Reilly, C.C. 2005. Relative susceptibility of peach cultivars to fungal gummosis (botryosphaeria dothidea). Journal of American Pomological Society. 59(2):111-116.

Interpretive Summary: Peach fungal gummosis is a debilitating foliar disease affecting many plant species including peach. If left uncontrolled on susceptible peach varieties, it can cause yield losses of 25 percent to 40 percent. At this time there are no chemical controls available. Currently, orchard sanitation, i.e., pruning of afflicted limbs and removal of this inoculum from the orchard, is the only management program available. The relative susceptibility of most commercial peach varieties is unknown. A trellis-mister system that had been proven effective in providing high, uniform fungal gummosis inoculum pressure was utilized to determine the relative susceptible of 25 commercially important peach varieties. Significant differences in susceptibility were observed. Several important peach varieties, Summergold, Flameprince and O'Henry, were found to be highly susceptible to this disease. The two most susceptible classes included varieties that represented 35 percent of the southeastern United States peach acreage. Growers need to be wary of planting these varieties on sites with high inoculum pressure and should utilize best management practices, including orchard sanitation and timely irrigation, to minimize inoculum and disease impact, respectively. In the absence of an effective spray program to control this disease, genetic resistance would be a highly desirable alternative. The methodology utilized in this work could be used to screen parents and selections in a peach variety breeding program.

Technical Abstract: Peach fungal gummosis, incited by Botryosphaeria dothidea (Moug.:Fr.) Ces. And De Not., has been shown to significantly depress growth and yield on susceptible peach cultivars. Little is known about the relative susceptibility of commercially important peach cultivars utilized in the southeastern United States. A trellis system equipped with an automated misting system was used to deliver inoculum from infected peach prunings to peach trees planted beneath the trellis. Peach prunings inoculated with B. dothidea were placed on the trellis wires above the newly planted trees. Intermittent misting of the trellis occurred during May and June of the first year; then the pruned shoots were removed. Disease severity was evaluated in November of the following growing season after visible symptoms developed. Significant variation in disease susceptibility was detected across the cultivars tested. Of the 25 cultivars tested, `Summergold' was the most susceptible and `Redskin' the least.

Last Modified: 12/21/2014