72 
BULLETIN &57, U. S. DEPARTMENT OE AGRICULTURE. 
IMPORTANT DATES IN THE LIFE HISTORY OF CRONARTIUM RIBICOLA. 
Table V shows some of the more important dates in the develop- 
ment of the white-pine blister rust and their variation according to 
locality. These dates are rarely the earliest or latest possible ones, 
but are based upon notes actually made respecting the point covered. 
It is hoped to extend this table greatly and approach nearer the 
actual date when each stage of development is reached by the fungus 
in the various regions. Southern New England is here made to 
include Massachusetts, Connecticut, and Rhode Island. Northern 
New York is understood to include approximately that part of the 
State lying north of a line between Glens Falls and Oswego. The 
Lake States include Michigan, Wisconsin, and Minnesota. Similar 
data for Europe are given in the last columns of the table for the 
sake of comparison. 
Table V. — Important dates in the life history of Cronartium ribicola, as observed in 
America and in Eur ope. a 
[To economize space, the century digits 19 are omitted in noting the year of each observation; thus 
'09=1909.] 
United States. 
Dev ^?? Ient ! Southern 
noted 
New 
England. 
Southern I 
New York, I 
New Jersey,; 
and eastern : 
Pennsyl- ! 
Northern 
New 
England. 
Northern 
New York. 
Lake States 
Europe. 
Date. 
Local- 
, ity.& 
First closed blis 
ters 
Apr. 
Apr. 
'17 Apr. 30, '11 
'18 Apr. 28/17 
....] May 4, '18 
Apr. 15, '10 Apr. 26, '18 May 5, '17 
Apr. 7, '17 I Apr. 21, '19 Apr. 19, '18 
May 13, '18 Apr. 18, '19 
First open blis- 
ters 
Last yellow blis- 
ters 
First uredinia . . 
First telia. 
First pycnial f 
drops \ 
June 22, 
May 22, 
May 16, 
June 3, 
May 2,5, 
June 2, 
May 3, 
Apr. 17, 
Apr. 7, 
Mar. 28, 
June 3, '16 
June 13, '17 
May 29/18 
June 17, '16 
July 21/17 
June 19/ IS 
July 30/19 
June 21, '16 
June 7/18 
June 1/09 
July 27, '10 
May 5/11 
June 10, '13 
May 20/15 
Apr. 7/16 
Apr. 28/17 
May 16/18 
June 14, '09 
May 26/10 
June 9/11 
May 15/12 
June 6/13 
May 15/15 
May 15/16 
Apr. 29, '17 
Apr. 23, '18 
Apr. 7/19 
June 7/10 
July 1, '17 
July 21/18 
June 8/09 Mav 24/16 
May 12/10 | May 8/17 
June 10/13 
July 18/16 
July 24/13 
July 14/14 
May 20/17 
May 16/18 
May 23/19 
June 26/13 
July 24/16 
June 10, '17 
June 2/18 
June 6/19 
July 26/13 
June 7/18 
Apr. 26/18 
Apr. 23, '19 
Apr. 19/18 
Apr. 22/19 
Apr. 16, '90 
Apr. 15/01 
Apr. 7/09 
Mar. 17, '18 
►Apr. 15/90 
Apr. 29, '96 
Apr. 28, '08 
June 12, '18 
June 26, '19 
July 25/09 
July 18/16 
June 28/17 
May 16/18 
May 23/19 
Aug. 23/17 
June 26/18 
June 30, '19 
July 3/18 
June 26/19 
June 24/17 
June 24/19 
Sept.l6/19e 
June 9/16 
June 12/17 
May 18/18 
June 5/19 
Mav 15 
May 9 
June 1 
May 19/18 j 
May 23 
Mav 30 
May 26 j 
June 2/19 

July 21/16 
June 12, '17 
July 8/18 
July 10/19 
Aug.l.. 
July 30. 
H 
M 
D 
F 
H 
Bo 
S 
B 
H 
D 
Bo 
F 
D 
B 
B 
B 
J M 
i s 
a Notations for Ontario, Canada: First open blisters— May 10, 1917, and June 22, 191S; first uredinia— 
June 24, 1915, and July 20, 1916; first telia— June 24, 1915. 
b Abbreviations used: B= Berlin, Bo=Bohemia, D= Denmark, F= France, H= Hamburg, M= Mu- 
nich, S= Silesia. 
c This date is an extraordinarily late one for aecia to be formed, but it is included here to show the possi- 
bility of the serial season being prolonged throughout the summer. 
