BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 35 
Pine-disease surveys are conducted to a Limited extern 4 each year as oppor- 
tunity arises. The purpose of these surveys is to determine the poinl at which 
local control measures should be instituted in the immediate future. The dis- 
covery of blister rust in a new section means that the white pines in that 
section can be expected to suffer serious loss unless local control measures, 
including Ribes eradication, are promptly carried out. 
Continued spread of the rust in the Last was evidenced by the finding o! 
the disease on white pine for the first time in Sussex and Passaic Counties, 
N. J.; Allegany and Garrett Counties, Md. ; Pendleton County, W. Ya.; Geauga 
County, Ohio; Dubuque County, Iowa; Pecker Oounty, Minn.; Chippewa, Jack- 
son, Marathon, Oneida, Adams, and Lincoln Counties, Wis.; and in Ontonagan, 
Leelanau, Emmet, Otsego, Alcona, and Sanilac Counties. Mich. Infection on 
Ribes was found for the first time in Nelson County, Ya., and in Frederick and 
Montgomery Counties, Md. 
In the West a new pine infection center was Located on Steamboat Creek, 
Douglas County, Oreg., about 100 miles from California, but scouting in the 
sugar pine forests of northern California failed to reveal the presence of the 
rust. In the western white pine region of northeastern Washington, northern 
Idaho, and northwestern Montana. 39 new centers of pine infection were re- 
ported, making a total of 129 for the region. All of these have developed 
within the last 12 years and there are undoubtedly many others still undis- 
covered. Of the 39 new centers, 8 were in northern Idaho and northeastern 
Washington on the Kaniksu National Forest, 1 on the Lolo National Forest, 
and 4 on the Cabinet National Forest in Montana. This is the first record 
of pine infection in Montana and in these national-forest units. 
Careful inspection and study of white pine areas show that very l'ttle new 
infection is occurring on white pines in the areas that have been brought under 
control by the eradication of Ribes, but in similar unprotected areas the rust 
is increasing rapidly and causing serious losses in white pine stands, particu- 
larly among the younger age classes. This steady spread and intensification of 
the rust in unprotected areas is indicative of the need for vigorous and continu- 
ous application of control measures to protect the valuable white pine forests 
of this country. 
Since the European or cultivated black currant ( Ribcs nigrum) is more sus- 
ceptible to blister rust than any other species of Ribcv, and is one of the chief 
agents in its long-distance spread and local establishment, the eradication of 
tins plant in white pine reg.ons is a general control measure that will be of 
material aid in checking the spread of the disease. During the past season 
70,927 of these plants were eradicated in six Northeastern and Lake States. 
This work has been completed in Rhode Island and in large parts of several 
other States. In the Appalachian region black currants are very scarce, and in 
the West they have been eradicated in the western white pine and sugar pine 
regions. 
In order to prevent the distribution of the disease through the movement of 
infected white pine planting stock, Ribes-free zones are establ.shed and main- 
tained around nurseries in cooperation with the owners. In establishing these 
zones all Ribcs are eradicated within 1.500 feet and all cultivated Mack cur- 
rants within 1 mile of the nurseries. These zones are kept free of Rith 
yearly inspection and reworking where necessary. During 1934 this work was 
carried on around 74 nurseries in is States, thus affording protection for mil- 
lions of white pines being grown for forest and ornamental planting. The 
number of these nurseries certified as having completely protected pines thai 
could be authorized for interstate shipment is d scussed in the report of tin 
Division of Domestic Plant Quarantines. 
Pre-eradication surveys were completed en 2,041,487 acres, of which 821,223 
acres were in the eastern white pine regions, and 1,220,264 in tie- w 
white pine and sugar pine region-. This work makes it possible t<> determine 
the location, the acreage, and the Ribes conditions on areas having sufl 
white pine values t«> warrant their protection from blister rust. The results 
of this work make it possible to decide on the eradication methods thai will 
accomplish most on each area and t<> make a reasonably close estimate ol the 
amount of work necessary to establish control. 
A survey of forest lands in Colorado ami Wy< ming was initiated in p 
determine the distribution and value of white pines in these States and to 
ascertain the number and species of Ribes occurring in these stands as a 
for applying control measures. The forests of these two State> aggregate 
about 31,500,000 acres within the boundaries of 24 national forests, 3 national 
