Apple Diseases in Illinois in 2003

Overall, the incidence and severity of apple diseases in commercial orchards in 2003 were very low throughout Illinois. In commercial orchards, apple scab was kept well under control. Apple scab, however, was present on crab apples throughout the state, causing defoliation during the summer. Scattered cedar-apple rust leaf spot was observed in some of the apple orchards, particularly in southern Illinois. The incidence of powdery mildew was very low. White rot of fruit and bitter rot were observed in some orchard. Sooty blotch and flyspeck were the most prevalent summer diseases in apple orchards in Illinois. Sooty blotch/flyspeck complex was epidemic in one orchard that did not receive proper spray program during summer. Fire blight was present in most of the orchards, but with very low incidence. Timely practice of the recommendations kept fire blight under control, even in the orchards with heavy infection in the past years.