Apple Diseases and their Management

Abstract

In this chapter the world’s most important apple diseases are described and common approaches for managing them are reviewed. The chapter does not provide a description of every disease that occurs on apple, a function that is better fulfilled by the APS Compendium of Apple and Pear Diseases (Jones and Aldwinckle 1990). Nor is this a comprehensive literature review on the selected diseases. I have attempted to include information on the geographic distribution of the disease, as well as providing a brief historical aspect for most diseases covered. I have also attempted to include the most recent references and scientific work related to each disease.The chapter is divided into nine sections. The first section is an introduction to apple production and pest management. Section two covers major diseases caused by fungi, including the ever important apple scab and powdery mildew. The next section covers diseases of the roots and crown with particular emphasis on Phytophthora root, crown, and collar rot. Sections four and five cover canker diseases, such as Nectria canker, and the summer fruit rotting diseases, respectively. The summer fruit rots include diseases such as black rot and white rot which could have been included in sections other than the one chosen; however, their importance as fruit rots takes precedence over their ability to cause leaf spotting or cankers. A small section on minor fungal diseases precedes an important section 7 on bacterial diseases. Here the management of fire blight is covered in detail. Section 8 focuses on the important and difficult-to-manage post harvest diseases such as blue mold. The last section addresses virus and virus-like diseases of apple.