4 BULLETIN 116, U. S. DEPARTMENT OF AGRICULTURE. 



had its top entirely dead above that point. Numerous small branches 

 were found on other trees in a similar condition. A number of other 

 trees of the same age apparently have been killed in a similar way, 

 as they have been dying for years and have had to be removed, one or 

 two at a time. While it takes a long time for the destructiveness of 

 this disease to reach its climax in any given locality, there can be no 

 doubt that if it finally becomes established and generally distributed 

 in our forests it will be the worst enemy the white pine has here, as is 

 stated to be the case in certain European countries. 1 It has become 

 so thoroughly established in Europe that there is no hope of eradi- 

 cating it there, but there is yet time to suppress it here if the danger is 

 once generally realized. Even with conditions as they are in Europe, 

 one of the most prominent plant pathologists of Germany recom- 

 mends the energetic fighting of this disease. 2 If such action is 

 advisable in Europe, even more drastic action is certainly proper in 

 this country. 



CAN THIS DISEASE WINTER OVER ON RIBES? 



Late in 1912 F. C. Stewart asked the writer to take part in a 

 cooperative experiment to try to determine whether this disease can 

 winter over on dormant Ribes stock and thus be carried from one 

 place to another in stock which has previously been diseased. Two 

 hundred 2-year-old Ribes nigrum plants which had been heavily 

 rusted by Cronartium ribicola in the late summer and early fall of 1912 

 were sent to the writer at Washington, D. C, about December 1. 

 They were promptly heeled in out of doors until February 1, when, 

 according to agreement, they were potted and brought into the 

 greenhouse. They started quickly and made a very vigorous growth. 

 They were examined several times for the presence of Cronartium 

 ribicola, but none was found. The experiment was concluded about 

 May 20 because of the writer's absence after that date. Parallel 

 tests were made at Geneva and Ithaca, N. Y., Lafayette, Ind., 

 Amherst, Mass., and New Haven, Conn., 300 plants being used. 3 

 The results were entirely negative. The evidence furnished by the 



i Bos, J. Ritzema. Phytopathologisch laboratorium Willie Commelin Scholten. Verslag over de inlich- 

 tingen gegeven in 1900. In Landbouwk. Tijdschr., jaar 9, p. 77. 1901. 



Fisher, W. R. Experimental plantations at Coopers Hill. In Quart. Jour. Forest., v. 3, no. 3, p. 229. 

 1909. 



Fron, Georges. Nouvelles observations sur quelques maladies des jeunes plants de Coniferes. In Bui. 

 Soc. Mycol. France, t. 27, no. 4, p. 476-481. 1911. 



Lind, Jens. Danish fungi as represented in the herbarium of E. Rostrup, p. 2S1-283. Copenhagen, 1913 



Neger, F. W. Die Nadelholzer ... p. 110-111. Leipzig, 1907. 



Somerville, W. Peridermium strobi, the blister of Weymouth pine. In Quart. Jour. Forest., v. 3, no. 3, 

 p. 232-236. 1909. 



Watson, J. O. The Woburn forests. In Gard. Chron.,s.3, v. 52, p. 422. 1912. 



2 Tubeuf, Carl von. tlber die Verbreitung von Baumkrahkheiten beim Pflanzenhandel. In Mitt. Deut. 

 Dcndrol. Gescll., p. 156-163, 1904. 



3 Stewart, F. C, and Rankin, W. H. Can Cronartium ribicola overwinter on the currant? In Phyto- 

 pathology, v. 4, no. 1, p. 43. 1914. 



