LIBRARY 
CEREAL CROPS & DISEASES* 
JOURNAL OF MCMM, RESEARCH 
Vol. XXXI Washington, D. C., November 15,1925 No. 10 
LONGEVITY OF THE TELIOSPORES AND ACCOMPANYING 
UREDOSPORES OF CRONARTIUM RIBICOLA FISCHER 
IN 1923 1 
By Perley Spaulding, Pathologist , and Annie Rathbun-Gravatt, Junior 
Pathologist, Office of Forest Pathology, Bureau of Plant Industry, United States 
Department of Agriculture 
INTRODUCTION 
This paper gives the results of investigations of an isolated problem 
connected with the life history of the. white-pine blister rust. It 
may not be amiss, therefore, to indicate its relation to the general 
problem. These investigations show that the teliospores, which give 
rise to the sporidia (which alone can infect pines), may survive outdoor 
conditions from the time of the formation of the first ones in the season 
until after winter has set in. Little is yet known of the period during 
which pines may be infected, but it is presumed that it includes the 
period of telial formation and possible germination. It is important, 
then, to know how long and how late in the season teliospores may 
survive and form sporidia, and the probability of their doing so. 
In the late fall and early winter of 1921 the senior writer tested the 
longevity of the teliospores of Cronartium ribicola Fischer {16)? 
While the results were satisfactory for the period covered (September 
21 to December 8), it was felt that such tests should begin earlier in 
the season of production of the teliospores ( 17 , p. 68) in order to get 
an idea of the maximum telial longevity under natural conditions. 
What may happen to the teliospores which are formed earliest in the 
season has received little direct attention, and this may be of con¬ 
siderable importance. Accordingly, in 1923 the writers made another 
study with this especially in mind. These tests began August 1, 
which was the earhest date at which a large enough supply of telial 
columns could be obtained, and continued until October 31. From 
August 1 to October 10 the work was carried on at Warrensburg, 
N. Y., and from October 10 to 31 at Bethel, Vt., under similar con¬ 
ditions. When the experiments were discontinued on October 31 
the teliospores in. several lots of material were still germinating 
strongly. The work of 1921 (16) showed conclusively that telio¬ 
spores of this fungus will readily survive and germinate under the 
conditions of early winter in Vermont. Judging from the vigor of 
their germination and the fact mentioned in the preceding sentence, 
there was no reason to suppose that these persisting teliospores in 
the present experiments would lose their viability for several weeks 
after October 31. In view of these conclusions and the pressure of 
other work which required that these tests be concluded as soon as 
possible, no attempt was made to continue until the viability of all 
of the teliospores was exhausted. 
1 Received for publication Mar. 3, 1925; issued January, 1926 
> Reference is made by number (italic) to “Literature cited,” p. 1015. 
Journal of Agricultural Research, Vol. XXXI. No. 10 
Washington, D. C. Nov. 15,1925 
Key No. G-506 
74780—26f-1 
( 901 ) 
UBHAry 
CEREAL investigations. 
