160 PLANT DISEASES 



Smith, Gard. Chron., March 2nd, 1889, p. 2; 1889, 

 p. 2 7 5, figs. 



Ludwig, Lehrbuch der niederen Kryptogamen, p. 335. 



Oudemans, Verslag Gew. Verd. der Wis-en Nat. AfdeeL, 

 1897. 



DOUGLAS FIR BLIGHT 



{Sclerotinia douglasii, Massee. 

 =Botrytis dotiglasii, Tubeuf.) 



Seedlings and young trees of the Douglas fir (Pseudo- 

 tsuga douglasii, Carr.) and Wellingtonia {Sequoia gigantea, 

 Lindl. and Gord.) sometimes have the lead and upper- 

 most shoots destroyed by the Botrytis form of Sclerotinia 

 douglasii. The same fungus appears to attack Juniperus 

 communis. A brownish-grey mould appears on the 

 branches, which soon become curved and finally die, the 

 needles in the meantime falling off. The Botrytis con- 

 tinues to form conidia on the fallen leaves, and minute 

 black sclerotia are formed on the dead branches. Several 

 young plants of Sequoia gigantea were killed at Kew by 

 this fungus. 



PREVENTIVE MEANS. If detected at an early stage, 

 spraying at intervals with Bordeaux mixture or potassium 

 sulphide solution would destroy the conidia, and check the 

 spread of the disease. Badly infected trees should be 

 removed and burned. 



Tubeuf, Beitr. z. Kenntniss d. Baumkr., 1888. 



