New York Agricultural Experiment Station. 109 



fungus under favorable conditions may wilt down and destroy, 

 within a day or two, whole boxes of lettuce seedlings. The dis- 

 ease is also readily induced by using pure cultures of the fungua 

 for inoculation purposes. 



What is apparently the same fungus has been found several 

 times as a disease of maturer lettuce plants. After the presen- 

 tation of a preliminary report upon rhizoctonial diseases before 

 the Society for Plant Morphology and Physiology in New York, 

 December, 1898, we received from Mr. R. E. Smith, Amherst, 

 Mass., lettuce plants showing a severe rotting of the leaves. 

 There was no doubt about the characters of the fungus, and we 

 determined it for Mr. Smith as the Rhizoctonia of lettuce. From 

 the characters of the parasitic material, as well as from pure 

 cultures, we considered it identical with the damping-off fungus. 

 The specimens received showed no rotting of the stem, the 

 leaves being the seat of attack. On the older lower leaves the 

 leaf blades alone are affected; but the more delicate inner leaves 

 succumb entirely, blackening and decaying with the progress of 

 the disease. Hyphae^ of the fungus occurred scantily over the 

 leaf surface, and a short tufted growth might be found on the 

 inner side of the petioles. These tufts were brownish-white or 

 tawny in color and not so dark as the corresponding growth 

 in culture. 



During the past winter this fungus has also been found by 

 Mr. Rolfs on greenhouse lettuce plants at Rochester. 



Again, Atkinson^ found a form of the sterile fungus studied 

 by him in Alabama, causing damping-off of lettuce seedlings at 

 Ithaca. 



Occurring, then, in such widely separated regions it is very 

 probable that it is a fungus very generally distributed. 



'Compare Stone, G. E., and Smith, R. E. The Rotting of Greenhouse 

 Lettuce, Bulletin 69, Mass. Agl. Exp. Sta. (Hatch), p. lG-17, 1900. 

 'Atkinson, Geo. F. L c. 



