14 



DISEASES OF ECONOMIC PLANTS 



The California vine disease in 1892, $10,000,000. Pierce. 



Wheat rust in the United States, 18981 $67,000,000. Galloway. 



Wheat rust in Illinois, 1885, $1,875,000. Burrill. 



Violet, leaf spot in the United States, 1900, $200,000. Dorsett. 



Peach leaf curl in the United States, 1900, $2,335,000. Pierce. 



Potato late blight in New York, 1904, $10,000,000. Stewart. 



Oat smut in the United States, annual, $6,500,000. Orton. 



Wheat loose smut, United States, annual, $3,000,000. Orton. 



Wheat bunt in the United States, annual, $1 1 ,000,000. Orton. 



Potato blight in the United States, annual, $36,000,000. Orton. 



SYMPTOMS OF DISEASE 



Every part of a plant — root, stem, leaf, fiower, fruit, 

 bark, wood, veins — is subject to disease, and the same 



disease may be mani- 

 fest in many, even 

 all, of these parts at 

 once. 



Rot is perhaps the most 

 conunon symptom 

 of disease to be 

 noted in any plant 

 part. Rot is of 

 many characters, 

 — soft, wet, dry, 

 hard, offensive or 

 inoffensive of odor. 

 Blight is a symptom 

 often exhibited 



Fia. 3. — Cowpea leaf spot (amerosporioae) . 

 Pycnidia scattered throughout, x 4. Original. 



by leaves, roots, stems, flowers, or fruit. It indi- 

 cates complete death of the part affected, may be 



