120 FOREST PROTECTION 



VII. Diaporthe parasitica (discovered by Dr. Murrill) is 

 the worst treekilling disease yet described in 

 the United States. It tends to exterminate the 

 chestnut trees from New York to Virginia, and 

 is spreading southward. Entering the cambial 

 layers of the tree and notably those of its branches 

 without the requirement of preceding wounds, 

 the mycelium actually "girdles" the living trees 

 (W. A. Murrill, in Jour. N. Y. Bot. Garden 7: 

 143-153; Bull. No. 149, Bureau of Plant Indus- 

 try, p. 22). 

 VIII. Hypoderma strobicola is the "needle blight" of the 

 white pine and appears to be a dangerous para- 

 site on Pinus Strobus. Compare Tubeuf's "Dis- 

 eases of Plants," english edition by W. G. Smith, 

 p. 233. Tubeuf claims that the disease may 

 devastate whole tracts of forests. A disease of 

 the white pine similar to that described by Tubeuf 

 has been reported from Massachusetts (various 

 articles in Woodland and Roadside), from Wes- 

 tern North Carolina and from eastern Tennessee, 

 and is being studied by the pathological divis- 

 ions of the U. S. Dept. of Agriculture. Compare 

 Circular No. 35, Bureau of Plant Industry. 



IX. "Damping-off" is a disease of seedlings soon after 

 germination dreaded by all nurserymen, and 

 decimating many natural regenerations (birch!). 

 The fungi causing the disease are undescribed. 

 H. Fungus species worthy of note which are technically obnoxious. 

 The genus Polyporus (including Trametes, Fomes, Boletus, 

 Polystictus, and Dcedalea) is responsible for the decomposi- 

 tion of heartwood in living trees frequently brought about 

 by the help of an enzym. 



Overaged timber is almost invariably attacked by Poly- 

 porus. The sporophores may appear in branch holes or scars, 

 and are, although the disease might be common, rare in many 

 species. 



Most noteworthy are the following Polypori: — 



I. Polyporus annosus (or Trametes radiciperda) , a root 

 fungus of conifers, attacks pole woods. Sporo- 

 phores under ground in roots. Wood turns brown 

 to begin with and is finally hollowed out. (Agric. 

 Year Book 1900, p. 207). 

 II. Trametes pini causes the heartwood rot (known as 

 "red heart") of pine; the punkiness and per- 

 haps the ring cracks of fir, long leaf, short leaf. 



