JOURNAL OF ACR1IIILTIM RESEARCE 
DEPARTMENT OF AGRICULTURE 
You. V Washington, D. C., January 24, 1916 No. 17 
A SERIOUS DISEASE IN FOREST NURSERIES CAUSED 
BY PERIDERMIUM FILAMENTOSUM 
By James R. Weir, Forest Pathologist , and Ernest E. Hubert, Scientific Assistant , 
Investigations in Forest Pathology, Bureau of Plant Industry 
In June, 1914, several seedlings of Pinus ponderosa Laws., with the 
stems severely infected with a disease caused by a species of Peridermium, 
were received from the Savenac nursery of the United States Forest 
Service, at Haugan, Mont. The seedlings were taken from the field¬ 
planting area located near the nursery. They had remained one year in 
the seed beds, one year in the transplant beds, and two years in the field. 
It seemed likely that the seedlings became infected while in the nursery, 
since the few yellow pines in the near vicinity of the area were free from 
the fungus. 
On July 2, 1914, CasiUleja miniaia Dougl., growing in abundance on 
the nursery site, was found bearing the fungus Cronartium coleosporioides 
(D. and H.) Arthur. 1 No other species of Cronartium was found. 
Evidence of the serial stage on left-over yellow-pine seedlings in the 
transplant beds brought the two stages in such close proximity it seemed 
certain that the fungus on the pine seedlings could be no other than 
Peridermium filamentosum Peck. Since the Savenac nursery has an 
annual output of 1,600,000 yellow-pine seedlings, it was evident that 
measures should be employed immediately to prevent the spread of the 
disease. 
On May 1, 1915, all of the 2-year-old yellow-pine seedling beds were 
found to be infected with the fungus. The seedlings were being prepared 
for shipment to the planting areas in the forests, and a thorough inspec¬ 
tion was made of all the bundled stock. All visibly infected seedlings 
were removed and burned. The seedlings remaining in the beds were 
examined, and the infected ones similarly destroyed. More than 4 per 
cent of the plants gave outward evidence of being attacked. Of the 
10,000 seedlings inspected 432 were removed and burned. Control 
1 Meinecke, E. P. Notes on Cronartium coleosporioides Arthur and Cronartium filamentosum. In 
Phytopathology, v. 3, no. 3, p. 167-168. 19x3. 
(781) 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
by 
Vol. V, No. 17 
Jan. 24, 1916 
G—72 
