azalea problems reference
Azaleas are generally very healthy plants when their basic cultural requirements are met. However, they are subject to a number of problems caused by infectious agents, insect pests, weather and nutrition deficiencies. Thorough descriptions of these problems and their control measures can be found in Compendium of Rhododendron and Azalea Diseases, American Phytopathological Society, 1986, ISBN 0-89054-075-6. Its table of contents is shown here, with links to some excerpts and summaries by permission.
Introduction 34 Diseases Caused by Nematodes 2 Rhododendron and Azalea Diseases 35 Diseases Caused by Algae 2 Infectious Agents 35 Algal Leaf Spot and Stem Infection 3 Noninfectious Agents 3 Disease Control Part II. Insect Pests 37 Black Vine Weevil and Other Weevils Part I. Diseases Caused 39 Rhododendron Borer by Infectious Agents 40 Scale Insects and Relatives 4 Diseases Caused by Fungi 41 Other Sucking Arthropods 4 Phytophthora Root Rot 43 defoliators 8 Armillaria Root Rot 43 Establishing a Pest Management Program 9 Phymatotrichum Root Rot 10 Pythium and Rhizoctonia Damping-Off and Root Rot Part III. Diseases Caused by Noninfectious Agents 10 Botryosphaeria Dieback 45 Moisture Stress, Heat Injury, and Winter Injury 11 Phomopsis Dieback 46 Mineral Nutrient Deficiencies and Toxicities 12 Phytophthora Dieback 48 Air Pollution Injury 15 Phytophthora syringae Blight 50 Pesticide Phytotoxicities 17 Other Twig Blights 17 Cylindrocladium Blight and Wilt Part IV. Beneficial Organisms 20 Rhizoctonia Web Blight 52 Mycorrhizae 21 Leaf and Flower Gall 22 Ovulinia Petal Blight 53 Aid to Diagnosis 24 Powdery Mildew 25 Leaf Spots 54 Common Names of Rhododendron and Azalea Diseases 26 Rusts 29 Diseases Caused by Bacteria 57 Glossary 29 Crown Gall 30 Diseases Caused by Viruses 61 Index 31 Rhododendron Necrotic Ringspot Color Plates (following page 30) 34 Mosaic and Leaf Spot 34 Diseases Caused by Higher Plants 34 Dodder