New York AGRICULTURAL EXPERIMENT STATION. 439 
insects or fungi. The young bark of stone fruit trees may be 
nearly covered with gum pockets as a result of bruises from hail 
stones. Wounds made in pruning are often followed by a flow of 
gum. It has been shown by some experiments that where the 
peach is pruned during the period of greatest vegetative activity, 
1. €., from April to August, there is a greater production of gum 
in the wounds than where the pruning is done later”. 
When gumming results from adverse conditions of environ- 
ment, of from over bearing, excessive pruning or any other cause 
which severely checks growth, it may often be remedied by mak- 
ing the conditions as favorable for growth as possible, as, for 
example, by frequent tillage, by the use of stable manure or other 
fertilizers, by draining the soil, by thinning the fruit to prevent 
overproduction and by treatment against diseases and injurious 
insects.” | 
LEAF CURL. 
(Hxoascus deformans (Berk.) Fckl.) 
Description.— The name is descriptive of the disease. The 
disease is caused by a fungus which not only attacks the leaves 
but may be found in the twigs as well. The curled leaves become 
distorted, crumpled, enlarged and curled. The disease may often 
be detected when the leaves first start from the buds in spring. 
The diseased leaves eventually fall so that in early summer the tree 
may be almost defoliated. In 1898 the disease caused a loss of 
many thousands of dollars to the fruit growers of the State by 
injury to the trees and by the premature dropping of the fruit 
which followed the loss of the foliage. 
Treatment.— It appears to be demonstrated that leaf curl may 
be largely prevented by spraying with Bordeaux mixture,” 1-to-11 
28 Zeit. f. Pflanzenkrankheiten, 6 (1896): 58, 59. 
29 For a more complete discussion of this subject, see Beach, 8. A. ‘“ Gum- 
ming of Stone Fruits.” Amer. Gard., 19 (1898): 606. 
30 Some advise the use of copper sulphate solution, 1-to-15 or 1-to-20 for- 
mula, instead of the Bordeaux mixture, but we advocate the latter because it 
adheres so well. 
