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Peach tree tolerance to Cytospora leucostoma infections under water deficit and increased soil pH
Stephan Miller - Colorado State University. Jane Stewart- Colorado State University, Ioannis Minas- Colorado State University

High pH soils and a limited water supply, in combination with the canker pathogen Cytospora leucostoma, are major limiting factors to peach fruit production in Colorado growing conditions. Tolerance to C. leucostoma, in association with tolerance to abiotic stressors, are important peach cultivar selection criteria for growers. Selection of tolerant peach cultivars could lead to a decrease in C. leucostoma incidence and an increase in orchard longevity. Our specific objective was to evaluate differences in tolerance to C. leucostoma infections under water deficit, pH stress and normal conditions among thirteen peach cultivars. Trees displayed increased stress (leaf water potential) under higher soil pH and 40% deficit irrigation in green house conditions. Further, Cytospora leucostoma displayed a fitness increase on water deficit and increased soil pH trees. Cytospora leucostoma lesion sizes did not differ statistically amongst the different peach cultivars tested, in terms of lesion sizes. These results reinforce the necessity for proper management techniques including proper soil pH management and proper irrigation management in commercial orchards.