UNITED STATES DEPARTMENT OF AGRICULTURE 



s&f^ji. 



BULLETIN No. 611 



Contribution from the Bureau of Plant Industry 

 WM. A. TAYLOR, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



December 10, 1917 



WALNUT BLIGHT IN THE EASTERN UNITED 



STATES. 



By S. M. McMttbbak, 

 Assistant Pathologist, Office of Fruit-Disease Investigations. 



CONTENTS. 



Page, 

 Importance of the disease. .................. 1 



History of walnut blight 2 



The disease in the Eastern States. ...„.„ 4 



Page. 



Time of infection 



Control of walnut blight.... 5 



Summary, s .,„„,.,„,.„, 6 



IMPORTANCE OF THE DISEASE. 



The growing of the Persian (English) walnut in the eastern half 

 of the United States is receiving increasing attention and arousin^ 

 the interest of many. Persian walnut trees, mainly seedlings, either 

 isolated or in small groups or orchards, are by no means uncommon 

 in the States east of Lake Michigan and the Wabash River below the 

 latitude of New England. An indication of the number of such trees 

 now growing in this part of the country was contained in an address 

 by Prof. F. N. Fagan, of State College, Pa., delivered before the 

 Northern Nut Growers' Association in 1915, in which the statement 

 was made that as the result of a recent survey by that college the 

 "location of some 1,500 or 2,000 bearing trees ; ' had been ascertained 

 in that State. While there has been no effort to make a similar 

 survey in other Eastern States, so far as the writer is informed; his 

 personal knowledge and that of associates in the Bureau of Plant 

 Industry indicates practically the same proportion of Persian walnut 

 trees in the States of New York, Delaware, New Jersey, and Mary- 

 land. Isolated trees are known in lower Connecticut, southern Michi- 

 gan, Ohio, and Virginia. Several eastern nurseries are now spe- 



Note. — This bulletin is intended particularly for all engaged in propagating Persian 

 walnuts in those portions of the United States east of the Rocky Mountains. It is also 

 of scientific interest to plant pathologists. 

 13187° — 17 — BulL Gil 



