340 MANUAL OF FRUIT DISEASES 
spraying the pear foliage with bordeaux mixture 4-5-50 or 
lime-sulfur solution 1-50 will satisfactorily control Myco- — 
spherella leaf-spot. Three applications are sufficient in the 
orchard; (1) just after the petals fall; (2) two weeks later; 
(3) two weeks after the second application. In the nursery 
it is recommended that two-year-old budded pears be sprayed 
shortly after the new leaves open. Subsequent sprayings 
should be made at two-week intervals; three sprayings in 
all will prove profitable for two-year-old budded stock. But 
since one-year-old budded stock is rarely attacked to a damag- 
ing extent, it is regarded as unprofitable to spray such trees for 
this disease. 
REFERENCES 
Stewart, V. B. Some important leaf diseases of nursery stock. 
Septoria leaf-spot of the pear. Cornell Univ. Agr. Exp. Sta. Bul. 
358 : 216-219. 1915. 
Duggar, B. M. Some important pear diseases. I. Leaf spot. Cor- 
nell Univ. Agr. Exp. Sta. Bul. 145: 597-611. 1898. 
Barrus, M.F. Diseases of pears. Leaf spot. In The Fruit Industry 
in New York State. New York Agr. Dept. Bul. 79: 1049-1050. 
1916. 
SUPERFICIAL BaRK-CANKER 
Caused by Myzosporium corticolum Edg. 
A roughening of the bark of both pears and apples is exceed- 
ingly common in eastern United States. (See Apple, page 
130.) 
Frost-Insury , 
Caused by the action of low temperatures 
At times pear trees are severely damaged by frost. The 
trees are often planted on low, rich soil, and from their loca- 
tion are more subject to cold. A difference in elevation of 
