Las enfermedades del rododendro

HOW TO IDENTIFY RHODODENDRON AND AZALEA PROBLEMS
Washington State University Extension Bulletin 1229
COOPERATIVE EXTENSION

Washington State University

HOW TO IDENTIFY RHODODENDRON AND AZALEA PROBLEMS
By A. L. Antonelli, Extension Entomologist; R. S. Byther, Extension Plant Pathologist; R. R. Maleike, Extension Horticulturist, WSU Western Washington Research and Extension Center,Puyallup; S. J. Collman, Extension Agent, Snohomish County; and A. D . D a v i s o n , Superintendent, WWREC, Puyallup.

TABLE OF CONTENTS
AZALEA and RHODODENDRON CULTURE ..............................................................1 SYMPTOMS ................................................. 3-24 Missing Portions of Leaves .............................. 2-4 Root Weevils..............................................................2 Caterpillars ................................................................3 Sawflies....................................................................... 4 Spotting, Discoloration, or Dead Areas on Plant Parts ............................... 5-14 Physiological Leaf Spot ............................................ 5 Fungus Leaf Spot....................................................... 5 Azalea Leafminer........................................................ 6 Rhododendron Leafminer.......................................... 6 Marginal Leaf Necrosis .............................................. 7 Iron or Manganese Deficiency .................................. 8 Heat Damage (sunscald) ........................................... 9 Root Problems............................................................ 9 Nitrogen Deficiency/Wet Feet ................................... 9 Virus Diseases ..........................................................10 Bud Blight ................................................................ 10 Cold Injury/Buds ..................................................... 11 Frost Injury/New Growth....................................... 11 Leaf Senescence ....................................................... 12 Normal Bark Development ...................................... 12 Lacebug ..................................................................... 13 Chemical Injury ...................................................... 14 Curling, Distortion, or Misshapen Plant Parts ..................................15-17 Leafroller...................................................................15 Cold Response/Leaves ........................................... 15 Azalea Leaf Gall ...................................................... 16 Aphids ...................................................................... 17 Powdery, Granular, or Other Unusual Material on Leaves and/or Stems................................................... 18-22 Rust .......................................................................... 18 Powdery Mildew ............................................... 18-19 Sooty Mold/Bark Scale ........................................... 20 Lecanium Scale ....................................................... 20 Indumentum ...........................................................21 Lichens ..................................................................... 22 Algae ......................................................................... 22 Dieback, Total Decline, or Poor Performance ......................................... 23-24 Crown Girdling ...................................................... 23 Root Rots.................................................................. 24 Stem Diseases ........................................................ 24 Broken Branches ..................................................... 24 Mountain Beaver ....................................................24 Small Leaves ............................................................ 24 Planted Too Deep ................................................... 24 SELECTED REFERENCES...