SCLEROTINIA 263 



time attributed to a fungus called Sclerotinia douglasii (Mas- 

 see), or Botrytis douglasii (Tubeuf). It has, however, now 

 been shown that this fungus is identical with Sclerotinia 

 fuckeliana (De Bary), the cause of the vine disease. Attacked 

 seedlings are often killed outright during the first season ; the 

 leaves turn yellow and fall, and the branches become more or 

 less covered with tufts of grey, fluffy mould. At a later stage 

 numerous minute black sclerotia are formed in the bark. 

 The lead and upper shoots of older trees are also some- 

 times attacked. In addition to the Douglas fir (Pseudotsuga 

 douglasii), the Wellingtonia (Sequoia gigantea) and the juniper 

 (Juniperus communis) suffer from this disease. Other kinds 

 of conifers are also probably attacked. 



In the case of nursery stock spraying with Bordeaux 

 mixture will check the extension of the disease. Seedlings 

 that have the lead injured should be removed and burned, 

 otherwise the sclerotia present in the bark will form fruit the 

 following season, and a fresh outbreak will occur. 



Massee, G.,Journ. Board Agr., 1905. 

 Tubeuf, Beitr. Keuntniss Baumkr., 1888. 



Lettuce stem canker. Lettuce that is grown under glass 

 frequently suffers severely from a disease indirectly caused by 

 Sclerotinia fuckeliana (De Bary). The injury usually com- 

 mences on the stem near the ground, afterwards the leaves 

 are attacked, finally the entire plant wilts and dies. The 

 stem on examination presents a cankered appearance, and is 

 sometimes almost eaten through, so that the plant breaks off 

 at the root. The lower part of the stem and leaves are 

 covered with a dense greyish mould, called Botrytis cinerea 

 (Pers.), which is now known to be only a conidial condition of 

 the Sclerotinia. Now this Botrytis condition is abundant 

 everywhere on decaying and dead plants where it lives as a 

 saprophyte, but when conditions are favourable it often 

 becomes a parasite on living plants. The necessary condi- 

 tions are brought about when plants are grown in a very 

 damp atmosphere, with the soil constantly wet, and a lack of 

 proper ventilation. Under this kind of treatment the cell- 

 walls of plants are very thin, and the cells constantly dis- 

 tended with watery cell-sap, conditions under which Botrytis 

 is alone able to enter the living tissues of a plant. When 

 once inside the plant rotting commences at once. From the 



