Xew York Agricultukal Exterimext Statiox. 443 



ing' c'liaraetoristic galleries. Pri};atiiai takes place uiuler the bark, 

 the adults finally gnawing their way out. There are probably 

 several broods in one season. It attacks a variety of fruit tree^. 

 Treatment. — As a preventive measure trees should be kept in 

 a healthy, vigorous condition ; as such trees are less liable to attack 

 than weak ones. Trees which become badly infested should be 

 dug up and burned. 



PEAK DISEASES. 



FIRE BLIGHT. 



(Bacillus amylovorus (Burr.) De Toni.) 



Description, etc. — This disease shows itself in the dying of en- 

 tire twigs, large branches or even the tree itself. It is a bacterial 

 disease that has long been known but whose real nature was first 

 discovered in 1879 by Dr. Burr ill of Illinois. It was afterwards 

 studied very carefully at this Station by Dr. Arthur^*^ and more 

 recently by ]\lr. M. B. Waite ^' of the United States Department of 

 Agriculture. 



The disease usually makes its first appearance soon after the 

 blooming period. The young fruit clusters and the twigs bear- 

 ing them turn black. The leaves also blacken and die but do 

 not fall. If affected twigs are not removed the disease rapidly 

 works its way down into the larger branches. 



According to Waite^^ the blight germs do not live over winter 

 in the soil. Moreover, he finds that in the majority of the affected 

 branches even, the germs die soon after the close of the growing 

 season. It is only in a small proportion of the affected branches 

 that .the germs survive the winter. Such " hold over " cases, as 

 he calls them, become centers of infection during the following- 

 spring. Branches in which the germ is alive do not ?how " 

 definite line of demarcation between the healthy and diseased 



36 See Annual Reports of this Station, 1884: 357; 1885: 241: 1880: 275. 



37 Waite, M. B. The Cause and Prevention of Pear Blight. Year-Book U. 

 S. Dept. Agr., 1895: 295-300. 



38 Loc. cit. 



