Management: Management of apple scab is based on the application of fungicides to control leaf and fruit infections caused by overwintering ascospores. The use of resistant cultivars and sanitation practices are used to varying degrees, depending on the orchard system being used and the goals of the grower.

Chemical control: Apple scab is controlled almost exclusively with fungicide sprays. A variety of fungicide sprays with differing modes of action are available. When and how they are used depends upon their mode of action. Protectant fungicides prevent the spores from germinating or penetrating leaf tissue. To be effective, they must be applied to the surface of susceptible tissue before infection occurs. Occurrence of infection can be predicted with an accurate weather forecast and the infection period table. Protectant fungicides are applied routinely at 7 to 10 day intervals or according to anticipated infection periods. Postinfection fungicides control the scab fungus inside leaves and fruit. These chemicals can penetrate plant tissues to eliminate or inhibit lesion development. The ability of these fungicides to stop infections is limited to a few hours, or up to few days (depending upon the specific fungicide), and often varies with temperatures during the first 24 to 48 hours after infection. Some fungicides can inhibit the fungus even later into the incubation period (the time between infection and the appearance of symptoms). Eradication of scab lesions after they appear does not usually occur, but can be achieved with the proper rate and timing of certain fungicides. The selection of fungicides for management of scab is based on several factors, including the entire spectrum of other diseases that must be managed at that time, the potential for resistance in the scab fungus to the selected chemical, the history of the disease in a particular orchard, the final market for the fruit, and other social and economic factors. Good horticultural practices, such as proper site selection, tree spacing and annual pruning, facilitates chemical control by improving spray coverage and reducing the length of wet periods.

Sanitation: Prevention of pseudothecial formation in overwintering apple leaves would probably eliminate scab as a serious threat to apple production in the U.S. Unfortunately, complete elimination of psuedothecia is not possible under orchard conditions with current methods. The potential for severe scab can be reduced with several methods that vary in practicality, depending on orchard size. Leaf pickup and destruction in late autumn can be employed if orchard size is extremely small; although diseased leaves from neighboring areas can be blown in. Flail mowing in late autumn to chop litter can help reduce numbers of pseudothecia, thus reducing inoculum in the following spring. Applications of 5% urea to foliage in autumn can hasten leaf decomposition, thus reducing formation of pseudothecia. Applications should be made just prior to leaf fall to avoid stimulating tree growth and predisposing the trees to winter injury. Since they are not 100% effective in destroying inoculum, sanitation practices are ineffective in years when disease incidence is high.