THE FOREST NURSERY 357 



The disease spreads slowly and seldom does serious damage in 

 the United States. Whenever it appears, however, the infested 

 trees should be promptly pulled up and destroyed. It usually 

 appears over areas from a few feet up to several yards in extent 

 often killing every tree in the infested area. 



Needle-cast caused by Lophodermiwn pinastri, although one of 

 the most serious diseases in European nurseries, has not as yet 

 been introduced into the United States. In Germany it is known 

 under the name "Schutte" and is recognized as the commonest 

 cause of the blight of pines both in the forest nursery and in the 

 plantation. Its presence is first made known by the reddening 

 of a few isolated needles in the early autumn which turn brown, 

 develop fruiting bodies of the fungus, and fall from the tree be- 

 fore winter. It progresses rapidly the following spring and often 

 destroys all foliage by the latter part of May. It is believed by 

 Hartley and others to be almost certain to cause trouble in forest 

 nurseries in the United States in the future. The disease is con- 

 trolled in Germany and elsewhere in Europe by spraying with 

 Bordeaux mixture in midsummer. 1 



8. DAMPING-OFF. Damping-off is a general term applied to 

 the destruction of young plants by parasitic fungi immediately 

 after germination. It is a serious hindrance to raising most coni- 

 fers and small-seeded broadleaved species. The disease is gen- 

 erally the most destructive under moist conditions, particularly 

 when the air is hot and humid. It is caused by species of Pyth- 

 ium, Rhizoctonia, Fusarium, and possibly Trichoderma. 2 



Pythium debaryanum and various species of Fusarium appear 

 to be the most destructive damping-off fungi in western nurseries. 

 A number of species of Fusarium have been very destructive in 

 the New York state nurseries, in the Vermont state nurseries, 

 and in some private forest nurseries in eastern United States. 3 

 Hartig 4 records the same or similar fungi as very destructive to 

 pine and spruce seedlings in Germany. 



1 Stumpff, K.: Die Schiitte und ihre Bekampfung. (Zeitschrift fur Forst- 

 und Jagdwesen, S. 675-687. 1900.) 



2 Spaulding, Perley: Damping off of coniferous seedlings. (Phytopath- 

 ology, vol. IV, p. 73. 1914.) 



8 Gifford, C. M.: The damping-off of coniferous seedlings. (Vermont 

 Agri. Exp. Sta., Bui. 157, p. 147. 1911.) 



4 Hartig, R.: Ein neuer Keimlingspilz. (Forstlich-naturwissenschaftliche 

 Zeitschrift, S. 432-436. 1892.) 



