The fungus that causes apple scab is now frequently resistant to the sterol-inhibiting fungicides, and manufacturers have moved on to using newer classes of fungicides. mso-list-type:hybrid; Infected leaves that are left under the tree are sources of disease for the following growing season. Black spot, leaf spot, scab, mildews and other diseases are killed by apple cider vinegar solutions. As the fruit matures it is much less susceptible. @font-face {mso-style-noshow:yes; Apples from a tree with a case of apple scab Apple scab is a potentially serious fungal disease of ornamental and fruit trees in the rose family. Extensive primary infections result in poor fruit set and make scab control during the season more difficult. font-family:"Times New Roman",serif; {mso-level-tab-stop:none; Should apple scab strike, make sure you remove and dispose of fallen leaves and fruit. Apple Scab. Choose scab-resistant varieties of apple or crabapple trees. mso-level-tab-stop:none; For proper pruning of apples, see Growing apples in the home garden. 7. mso-fareast-font-family:"Times New Roman";} Heavy infections can defoliate and weaken your apple trees. Some crabapples especially resistant to apple scab include M. ‘Adirondack’, M. baccata ‘Jackii’, M. ‘Beverly’, M. ‘Dolgo’, M. ‘Donald Wyman’, M. ‘Mary Potter’, M. ‘Molazam’ (Molten Lava), M. ‘Prairifire’, M. ‘Red Jewel’. This is especially important with apples, crab apples and pears. mso-fareast-theme-font:minor-latin; Thinning will promote more rapid drying of leaves which is less favorable for apple scab development. mso-themecolor:followedhyperlink; Learn more about our HOME GROWN commitment. When sprays are necessary, they should be applied between bud break and a month after petal fall. [CDATA[/* >