278 ANNUAL REPORTS OF DEPARTMENT OF AGPJCULTUKE. 



partly because the rust was not introduced as early as in tlie 

 Northeastern States, and then in onl}^ a few places. 



In western North America the blister rust was first found during 

 the autumn of 1921 on pines and currants at several points in south- 

 western British Columbia. Later it was found in northwestern 

 Washington on cultivated black currants at Sumas, Mount Vernon, 

 Beverley Park, and Port Townsend, and on two planted white pines 

 at Mount Vernon. 



Extensive field surveys during the past season by Federal, State, 

 and Dominion scouts show that blister rust is widespread through- 

 out the coast pine belt of British Columbia on both pines and cur- 

 rants and gooseberries. It was introduced there in 1910 or earlier 

 on imported nursery stock. Several large areas were found where 

 the disease is now epidemic on the pines. In one local area 40 

 per cent of the trees are dead and 100 per cent are seriously infected. 

 The rust was found also with more limited distribution on pines, 

 currants, and gooseberries at Kevelstoke and Beaton, east of the 

 dry belt in British Columbia. These points are located about 100 

 miles from the international boundary in the northern part of the 

 commercial western white-pine belt, which extends into eastern 

 Washington, northern Idaho, and western Montana. Repeated scout- 

 ing in these regions gave negative results. 



No trace of white-pine blister rust was found in the western 

 United States, except in that portion of Washington lying west of 

 the ridge of the Cascade Mountains. In this region the rust was 

 found principally on cultivated black currants on 170 properties 

 within the counties of San Juan, Island, T\^iatcom, Skagit, King, 

 Pierce, Clallam, Jefferson, Kitsap, Mason, Grays Harbor, and 

 Pacific. In the infected counties 2.1 per cent of the total number 

 of cultivated black currants inspected were found attacked by the 

 rust. Pine stands in this region were scouted intensively, but only 

 a single canker of 1917 origin was located. This was on a planted 

 pine at Blaine, "Wliatcom County, near the international boundary. 

 The scope of this work was ample to show that the disease was not 

 generally established there on pines and that the infection on Ribes is 

 the result of the general spread of the disease from heavily infected 

 pines in British Columbia. 



The general establishment of blister rust in the commercial western 

 white-pine areas will eventually cause severe economic loss unless 

 adequate measures for its control can be developed and applied under 

 western conditions. Owing to the more recent introduction of the 

 disease into western North America, as well as to differences in field 

 conditions, host plants, and climate, these factors must be studied 

 and their proper bearing on the spread of the rust ascertained before 

 the practicability of delaying its progress and the limitations of 

 local control can be fully determined. 



CHESTNUT BLIGHT. 



Chestnut blight has spread more rapidly in the Southern States 

 than it did in the North. A large advance infection of the disease 

 has been found covering parts of Greenville County in South Car- 

 olina and Henderson and Polk Counties in North Carolina. This 

 advance infection indicates that the death of the chestnut stand of 



