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



icola), fusiform rust (O. fusiforme), brown-spot needle blight (Scir- 

 rhia acicoJa), annosus root rot (Fomes annosus), Hypoxylon canker 

 (Hypoxylon pruinatum), oak wilt (Ceratocystis fagacearum), and 

 dwarf mistletoes (Arceuthobium spp.) . 



Selection and/or breeding to improve genetic resistance to specific 

 forest tree diseases is underway in the following genera : 



Castanea for resistance to Endoth'ia parasitica ; 



Populus for resistance to Septorla musiva; 



Ulmus for resistance to Ceratocystis ulmi and Morsus ulmi; 



Juniperus for resistance to Exosporium glomerulosum and Pho- 



mopsis juniperovora; 

 Pinus for resistance to Arceuthobium spp., Cronartium, ribicola, 



C. fusiforme, and Phytophthora cinna.momi; and 

 Pseudotsuga for resistance to RhabdocJine pseudotsugae. 



In addition, for all forest tree diseases our pathologists have been 

 directed to note any instances of apparent resistance and to take action 

 as needed to insure that the germ plasm is not lost. 



A recent development in the United States will stimulate increased 

 international cooperation in forest disease research. The United 

 States sells surplus agricultural commodities — wheat, cotton, and to- 

 bacco, for example — to many countries. Payment for these commodi- 

 ties is accepted in the currency of the recipient country and has re- 

 sulted in the accumulation of considerable U.S. credit balances in some 

 countries. In 1958 we were given the authority by Congress to use 

 a portion of these funds for agricultural and forestry research of 

 benefit to the United States. Since that time we have negotiated 234 

 foreign research projects, including 43 in forestry distributed as 

 follows: Europe 27, Asia 15, and South America 1. Five of the for- 

 estry projects are in forest disease research. Two are on the role of 

 mycorrhizae in tree nutrition, growth, and disease susceptibility (in 

 Finland and Poland) ; one is a survey of the diseases of native and 

 exotic conifers (in Spain) ; another is on the antibiotic relationship 

 of saprophytic soil fungi to forest tree root pathogens (in Poland) ; 

 and the remaining one is a study of the susceptibility of North Amer- 

 ican forest tree species to insects and diseases (also in Poland). We 

 are currently negotiating similar susceptibility studies in Columbia 

 and Uruguay, S.A. These research projects will contribute directly 

 to our Working Group objectives. 



In conclusion, I would like to say that we in the U.S. Department 

 of Agriculture will take advantage of every opportunity to carry out 

 research at home and abroad that will provide a better understanding 

 of the nature and cause of destructive forest diseases and will lead 

 to improved methods of reducing disease losses. 



United States 



A. J. Hiker 



Professor of Plant Pathology and Forestry. University of Wisconsin, 

 Madison, Wisconsin, U.S.A. 



Studies are under way at Wisconsin on some potentially dangerous 

 diseases. 



