Colorado Plant Diseases 
3 
CONTENTS 
Page 
Introduction '5 
PART I— The Nature of Plant 
Diseases 6 
Parasitic Diseases 7 
Bacteria 7 
Slime molds 8 
Fungi 9 
Non-parasitic Diseases 15 
Diseases of Uncertain Cause. ... 20 
PART II— Diseases Affecting Colo- 
rado Crop Plants 21 
ALF ALFA- 
Bacterial Blight 21 
Leaf-spot 22 
Yellow-leaf Blotch 23 
Downy Mildew 23 
Dodder 24 
APPLE— 
Fire Blight 24 
Scab 25 
Black Rot 26 
Bitter Rot 27 
Powdery Mildew 28 
Crown Gall 29 
Nitre Injury 30 
Apple Rot; Blue Mold 31 
Black Mold 32 
Frost Injury 32 
Spray Injury 33 
Neglected Orchards 33 
APRICOT— 
Black Knot 33 
Brown Rot 33 
Fruit Spot 33 
Scab 33 
Crown Gall 34 
Frost Injury 34 
ASPARAGUS— 
Rust 34 
BEAN— 
Bacteriosis 35 
Anthracnose 37 
Stem Blight 37 
Rust 40 
Sunscald 40 
BEET— 
Root-rot 40 
Curly Top 40 
Leaf-spot (Cercospora beticola) 4 
Leaf-spot (Phoma betae) 42 
Nematodes 43 
BLACICBERRY— 
Anthracnose 43 
Leaf-spot 43 
Page 
CABBAGE— 
Black-rot 44 
Black-leg 44 
Yellows . 44 
Club-root .' 45 
CELERY— 
Late Blight 45 
Early Blight 46 
Root-rot 46 
CEREALS— 
Covered Smut of Barley 47 
Loose Smut of Barley 48 
Corn Smut 47 
Oat Smut 49 
Flag Smut of Rye '50 
Kernel Smut of Sorghum 50 
Head Smut of Sorghum 50 
Covered Smut or Bunt of 
Wheat 51 
Loose Smut of Wheat 52 
Flag Smut of Wheat 52 
Stem Rust of Wheat, Oats, 
Barley and Rye 53 
Leaf Rust of Wheat 53 
Leaf Rust of Barley 54 
Leaf Rust of Rye 54 
Crown Rust of Oats 54 
Yellow Stripe Rust of Wheat, 
Barley and Rye 54 
Barley Stripe 54 
Ergot •• 55 
Take-all 56 
CHERRY- 
Black-knot 57 
Shot-hole 58 
Brown Rot 58 
CUCUMBER— 
Bacterial Wilt 58 
Downy Mildew 59 
CURRANT— 
Canker 60 
FLAX— 
Wilt 60 
GOOSEBERRY— 
Mildew 61 
MILLET— 
Smut 61 
PEA— 
Powdery Mildew 62 
Stem Blight 63 
PEACH— 
Scab 64 
Brown Rot 64 
Blight, or Fruit-spot 65 
Mildew 66 
