Pyrus is a large genus of shrubs and trees in the rose family. Pyrus communis, the common or European pear, is grown for its edible fruit. Pyrus calleryana, or Callery pear, originally imported from China to breed fire blight resistance into P. communis, is grown primarily for ornamental use. The ornamental Callery pear is one of the most widely grown trees in urban, residential and commercial landscapes. It is known for its early spring profusion of showy white flowers, fast growth and tolerance of difficult growing sites. Since the release of ‘Bradford’ in 1963, many ornamental cultivars have been introduced. Like other rosaceous plants, pears are susceptible to a number of diseases including fire blight, scab, rust, and leaf spot.