|Bertrand, P - UGA, TIFTON, GA|
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 5, 2002
Publication Date: N/A
Interpretive Summary: Peach tree fungal gummosis is widespread throughout the southeastern United States. Until recently, its economic impact on peach had been impossible to estimate since no effective controls were known. We achieved significant suppression of gummosis on Summergold peach utilizing fungicides in an intensive spray program. The best fungicide treatment provided significant improvements in tree performance compared to untreated trees. Yield increases ranged from 40-60 percent when gummosis was suppressed. Following cessation of fungicide treatments after the first 4 growing seasons, disease severity slowly increased in even the best fungicide treatment tested which indicates that a disease management program will likely be required throughout the lifetime of an orchard in order to achieve optimal performance.
Technical Abstract: Peach tree fungal gummosis caused by Botryosphaeria dothidea [(Moug.:Fr.) Cos & de Not] is widespread throughout the southeastern United States. Until recently, its economic impact on peach (Prunus persica (L.) Batsch) has been impossible to estimate since no effective controls were known. Significant, though not total, suppression of gummosis on 'Summergold' peach trees was achieved with an intensive 4-year spray program with Captafol. Captan was far less effective. Both trunk diameter and yield were negatively correlated with disease severity. After 8 growing seasons, Captafol-treated trees were 18% larger than untreated trees. Yields of mature Captafol treated trees were 40-60% higher than untreated trees. Following cessation of the spray program after 4 years, disease severity gradually increased on both Captafol and Captan treated trees. However, through 8 growing seasons, disease severity was significantly lower on Catafol treated trees.