CONTENTS 



What Causes Tree Diseases? 1 



Infectious Diseases — Fungi, 

 Bacteria, Viruses, Higher 



Plants 1 



Noninfectious Diseases — Unfa- 

 vorable Environmental Con- 

 ditions, Chemical Injuries, 



Mechanical Injuries 4 



Types of Tree Diseases 8 



Leaf Diseases — Powdery Mil- 

 dew, Leaf Spot, Scorch, Chlo- 

 rosis, Chemical Injury 8 



Stem Diseases — Canker, Gall, 

 Dieback, Witches'-Broom, 



Woodrot 17 



Vascular Diseases 22 



Root Diseases 23 



Diagnosis of Tree Diseases' 23 



Tools and Their T:ses 23 



Tree Therapy 26 



Spray Materials — Copper Sul- 

 fate and Hydrated Lime, Cy- 

 cloheximide, DDT, Dichlone, 

 Dodine, Ferbam, Methoxy- 

 chlor. Organic Mercury, Sul- 

 fur, Thiram, Zineb 26 



Feeding — Dry Feeding, Liquid 

 Feeding, Feeding Rates for 

 Deciduous Trees, Feeding 



Rates for Evergreens 28 



Watering 33 



Pruning 33 



Sanitation 34 



Wound Treatment 35 



Resistance and Immunity 36 



Arbor-Vitae — Winter Drying .... 37 

 Ash — Anthracnose, Scorch, Rust, 

 Cankers, White Mottled Rot ... 38 



Birch— Cankers 39 



Buckeye and Horsechestnut — 



Leaf Blotch, Scorch 40 



Catalpa — Verticillium Wilt 41 



Cherry — Rust, Brown Rot, Twig 

 Canker 41 



Chestnut— Chestnut Blight, 



Other Cankers 43 



Crab Apple — Scab, Rust, Fire 



Blight 44 



Elm — Dutch Elm Disease, Phloem 

 Necrosis, Wetwood, Verticil- 

 lium Wilt, Dothiorella Wilt .... 47 



Hackberry — Witches'-Broom .... 53 



Hawthorn — Rust, Fire Blight, 

 Leaf Blight 55 



Juniper — Cedar-Apple Rust, Ce- 

 dar-Hawthorn Rust, Cedar- 

 Quince Rust, Juniper Blight. . .56 



Linden — Verticillium Wilt 63 



Maple — Anthi'acnose, Tar Spot, 

 Scorch, Canker and Dieback, 

 Verticillium Wilt 64 



Mountain Ash — Fire Blight 67 



Oak — Anthracnose, Leaf Blister, 

 Rust, Smooth Patch, Dothio- 

 rella Canker, Oak Wilt, Shoe- 

 string Root Rot 68 



Pine — Needle Blight, Needle Cast, 

 Needle Rust, Sooty Mold, White 

 Pine Blister Rust, Diplodia Tip 

 Blight 76 



Poplar — Rust, Cytospora Canker, 

 Dothichiza Canker, Crown Gall . 80 



Redbud— Canker, Verticillium 



Wilt 82 



Spruce — Cytospora Canker, 



Diplodia Tip Blight 83 



Sycamore and London Plane Tree 



— Anthracnose, Canker Stain . . 85 



Willow — Tar Spot, Leaf Rust, 

 Cytospora Canker, Crown Gall. 91 



Trees Relatively Free of Diseases . 92 



The photographs reproduced in this circular were taken by the follow- 

 ing persons: J. Cedric Carter, William E. Clark, Ray R. Hamm, Robert E. 

 Hesselschwerdt, Charles L. Scott, and Wilmer I). Zehr. The drawings were 

 made by Robert E. Teegardin. The cover photograph, by Dr. Carter, shows 

 the first tree affected with Dutch elm disease found in Illinois. 



