28 U.S. DEPT. OF AGRICULTURE MISC. PUB. 9 39 



Of immediate interest, we have many studies in progress on the 

 principal diseases of Pinus, Populm, and Quercus, several of which 

 will be considered in detail. Examples are as follows : 



Diseases of Pinus spp. — 



Cronartium ribicola, blister rust of white or 5-needle pines ; 



Cronartium strobilinum, r>one rust of southern hard pines; 



Cronartium fusiform^, fusiform rust of southern hard pines; 



Cronartium comandrae, Comanclra rust of western hard 

 pines ; 



Peridermium harknessii, gall rust of western hard pines; 



Scirrhia acicola, brown-spot needle blight of longleaf pine; 



Elytroderma deformans, needle blight of ponderosa pine; 

 and 



Fomes annosus, root rot of conifers. 

 Diseases of Populus spp. — 



Hypoxylon pr-uinoMim. Hypoxylon canker of aspen. 

 Diseases of Quercus spp. — 



Ceratocystis fagacearum. oak wilt. 



In addition, we are investigating the heart rots of all species to de- 

 termine the causal fungi, how they enter living trees, how rapidly 

 they decay wood, and the relation of rot volume to tree age, vigor, 

 and site conditions. For all western conifers we are studying the 

 factors that regulate infection and intensification of the dwarf- 

 mistletoes, Arceuthobium spp., which are a major cause of loss in 

 forest productivity. For many diseases, particularly the Cronartium 

 rusts and the dwarfmistletoes, we are strengthening our research to 

 develop controls with systemic chemicals. 



Publications 



Federal research on forest tree diseases in the United States has 

 been carried on continuously since 1899. By the end of 1960 about 

 2,800 articles had been published on the cause and control of diseases 

 of forest trees and forest products. These were published as govern- 

 ment bulletins, in scientific journals, and in a wide variety of technical, 

 trade, and popular publications; Titles through 1953 are listed in 

 USDA Miscellaneous Publication No. 725, "Bibliography of Forest 

 Disease Eesearch in the Department of Agriculture." We plan to 

 publish additions to the bibliography at 10-year intervals. In the 

 meantime we issue annual lists of publications such as the one for 1960, 

 available for distribution at this Congress. Instructions on how to re- 

 quest copies of articles are attached. With few exceptions, publica- 

 tions of the U.S. Department of Agriculture are available at no cost 



Of the many recent publications on forest diseases issued by the 

 U.S. Forest Service, three by Dr. Perley Spaulding are of particular 

 significance to this Congress. They are USDA Handbooks Nos. 100, 

 139, and 197, respectively published in 1956, 1958, and 1961. No. 100 

 is titled "Diseases of North American Forest Trees Planted Abroad" ; 

 No. 139, "Diseases of Foreign Forest Trees Growing in the United 

 States" ; and No. 197, "Foreign Diseases of Forest Trees of the World." 



In 1955 we started a new series of publications known as Forest Pest 

 Leaflets. To date, 54 leaflets have been issued, of which 26 are on 

 diseases and 28 are on insects. These leaflets summarize for popular 



