Family Compositae 143 



gray mold. The fungus has two stages. Botrytis 

 cinerea Pers. of mlted lettuce leaves appears as a 

 gray mold, the other is the winter or apothedal stage. 

 American botanists have not as yet been able to con- 

 nect these two forms. It seems, however, that 

 IstvanfB* was able to confirm the work of De Bary, 

 who first indicated the relationshp of Botrytis cinerea 

 ^th Sclerotinia Fuckdiana. 



Lettuce Drop 



Caused by Sclerotinia libertiana FcM. 



Drop is a disease which is found wherever lettuce 

 is grown. The greatest damage is reported from the 

 South Atlantic States, North and South Carolina, 

 Alabama, Georgia, Florida, Louisiana, although the 

 trouble extends also to such States as Massachusetts, 

 New York, Ohio, Pennsylvania, Comiecticut, Rhode 

 Island, Wisconsin, Iowa, Washington, Vermont, 

 Maine, Maryland, Delaware, and Virginia. 



Symptoms. The term drop best describes the 

 symptoms of the disease. The first sign is a wilting 

 of the lower leaves (fig. 22), which is immediately 

 followed by a drooping of upper ones until the entire 

 plant is involved. The affected plant has a sunken 

 appearance as if scalded with boiling water. In 

 examining a dead plant, a white cottony fungus 

 growth is found on the under side of the lower leaves, 

 and near the moist regions at the stem end. 



' IstvaufiB, G. De, Ann. de I'institat central amp^L roy, Hongiois: 

 183-360. 1915- 



