BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 41 
reproduction and planting. The initial eradication of ribes has been 
completed on over 22 million acres of the net control area, and of this 
acreage about 7 million have been reworked. _ 
Control work during 1943 was carried on in cooperation with Fed- 
eral, State, and private agencies under the over-all leadership and 
technical direction of the Bureau. The eradication of ribes by all co- 
operating agencies resulted in the removal of 16,116,886 ribes bushes 
from 1,141,914 acres of control area, of which 467,270 were initial 
eradication and 674,644 rework. The details of this work by regions 
are shown in table 3. 
Table 3. — Ribes eradication work of all cooperating Federal, State, and private 
agencies for the calendar year 19-'{3 
Region 
Initial erad- 
ication 
Reeradi- 
cation 
Total 
Effective 
labor 
Ribes 
bushes 
destroyed 
Northeastern 
Acres 
92, 928 
284, 578 
50, 573 
8,927 
30, 264 
Acres 
275, 799 
278, 049 
58, 646 
27, 820 
34, 330 
Acres 
368, 727 
562, 627 
109, 219 
36, 747 
64, 594 
Man-days 
28,287 
10, 191 
15, 490 
47, 098 
50,115 
Number 
2, 574, 503 
817, 615 
2, 061,192 
3, 790, 528 
6, 873, 048 
Southern Appalachian 
North Central 
Northwestern (Idaho, Montana, and 
Washington) . . 
Pacific Coast (California and Oregon) 
Total - 
467, 270 
674, 644 
1, 141,914 
151,181 
16,116, 886 
SPREAD OF BLISTER RUST 
White pine blister rust has. been reported from 27 States. In Cali- 
fornia infection on ribes was found this year for the first time on the 
Tahoe National Forest, which extends the known distribution of the 
disease a few miles southward in the commercial sugar pine belt. Rust 
on ribes also was found in Marin County along the California coast, 
bringing the disease close to the San Francisco Bay district. Within 
the sugar pine area of California and Oregon, where rust has been 
found, a careful search was made for centers of pine infection in all 
control units. In these centers the cankers on the pines and the ribes 
in the vicinity were removed. This action temporarily retards the 
intensification and spread of rust, thus allowing more time for eradi- 
cating ribes in additional sugar pine stands in advance of the disease. 
In the western white pine type of pastern Washington, northern 
Idaho, and western Montana the rust is well established and increas- 
ing on those portions of the control area where ribes is still preva- 
lent. In 1943 cankers resulting from pine infection in 1941 began to 
appear. The amount of this infection, particularly in areas where 
the disease became established in 1937 and on which ribes eradication 
had not been performed in the meantime, is comparable to the heavy 
infection wave of 1937. Since 1923, when the rust first reached the 
western white pine region, more than the average amount of annual 
pine infection occurred in 1927, 1933, 1937. and 1941. 
In the southern Appalachian region tnere was an increase in the 
number of infected counties, and continued intensification of the dis- 
ease in unprotected white pine areas. Blister rust was found for the 
first time on ribes in Bedford, Botetourt, and Washington Counties 
in Virginia, and on white pine in Giles, Nelson, and Rockbridge Coun- 
ties. The rust has now been found on ribes in 29 of the 34 counties in 
Virginia making up the control area and on pine in 18 counties. Also 
