FOREST DISKASE SURVEYS. 



11 



always remains a great danger of infection spreading to the young 

 stock, with consequent loss. This has been shown in several recent 

 cases where forest nurseries were located in close proximity to dis- 

 eased trees and alternate hosts. At the forest nursery at Haugan, 



Fig. 12. — Fomes officinalis, chalk fungus, showing typical rot in lodgepole pine. Note the 

 white mycelium in the cracks. (Photographed hy G. G. Hedgcock.) 



Mont., yellow-pine seedling's became seriously infected with Cronar- 

 tium coleosporioides (Peridermium filamentosum Pk.). The disease 

 was transmitted by means of the alternate form of the rust occurring 

 on the Indian paintbrush (Castilleja miniata Dough), which was 

 found growing at the very edge of the nursery beds. 1 A survey of 



1 Weir, J. R., and Hubert, E. E. A serious disease in forest nurseries caused by Peri- 

 dermium filamentosum. In Jour. Agr. Research, v. 5, no. 17, p. 781-785. 1916. 



