Xew York Agricultural Experiment Station. 439 



insects or fimgi. The voime; 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, 

 i. e., from April to August, there is a greater production of gum 

 in the woimds than where the pruning is done later^. 



When ffummine: results from adverse conditions of environ- 

 raent, 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. 



(Exoascus 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-ll 



28Zcit. f. Pflanzenkrankheiten, 6 (1896) : 58, 59. 



29 For a more complete discussion of this subject, see Beach, S. A. "Gum- 

 ming of Stone Fruits." Amer. Gard., 19 (1898) : 606. 



30 Some advise the use of copper sulphate solution, l-to-15 or l-to-20 for- 

 mula, instead of the Bordeaux mixture, but we advocate the latter because it 

 adheres so well. 



