FOREST PROTECTION 119 



VII. Fungi destroying the sapwood of dead trees and of logs. 

 VIII. Fungi destroying the heartwood in living trees. 

 IX. Fungi destroying timber, ties, poles and posts after 

 manufacture and whilst in use. 



G. Fungus species worthy of note which are physiologically obnoxious. 

 I. Agaricus melleus (honey fungus) is a champignon 

 attacking and killing conifers four to fifteen 

 years old. White pine suffers very badly. The 

 disease spreads underground through the so- 

 called rhizomorpha (strong threads of mycel- 

 ium). The soil at the basis of affected plants 

 is charged with exuded rosin. Comp. Bull. Plant 

 Industry, No. 149, page 23. 



II. Aecidium pini attacks the needles and the young 

 bark of pine saplings. The spores enter by a 

 wound and the spread of the mycelium in the 

 cambium causes hypertrophical formations, es- 

 pecially on the main stem. The teleutosporous 

 generation has a Senecio species for its host 

 (Coleosporium senecionis). 



III. Peridermium cerebrum (family Uredineos) kills two 



year old lodgepole pines as well as other pines. 

 (Agric. Year Book 1900, p. 200). 



IV. Peridermium strobi, known as the blister of the white 



pine, has Pinus cembra for its original host. 

 Whilst it does not injure this species seriously, 

 its attacks are deadly to our white pine during 

 its juvenile stage. In old trees well protected 

 by heavy bark, the tops and branches alone are 

 affected. The disease is frequent abroad; and 

 stringent measures should prevent it from en- 

 tering into the United States. The uredal form 

 of the fungus (Cronartium ribicolum) forms blotches 

 on the leaves of the currant (Ribes). Compare 

 Quarterly Journal of Forestry, July, 1909, p. 232. 

 V. A Gymnosporangium causes the "Cedar apples" of 

 red cedar; see Bull. 21, Div. of Pathology, p. 8. 

 For. Bull. 31 (Red Cedar) p. 25. 



VI. Hysterium pinastri causes the shedding disease dreaded 

 in nurseries. Pine seedlings up to four years 

 old drop the needles of a sudden in spring. White 

 pine is little affected; strong seedlings are im- 

 mune. The disease spreads through old needles 

 on which the fungus lives saprophytically. Not 

 observed in America so far. 



