68 HATCH EXPERIMENT STATION. [Jan. 



it is of compiirativel}^ recent occurrence. Most growers, 

 however, know and fear it more than the rust or any other 

 carnation disease. It has been found that there are in reality 

 two distinct stem rots of the carnation, caused by two differ- 

 ent fungi. In one a soft rotting of the whole stem occurs 

 just at the surface of the ground, thus killing the plant 

 quickly and completely. This is caused by the Rhizoctonia 

 fungus described in our Bulletin No. 69 as the cause of a 

 lettuce rot, and what is said there in regard to this destruc- 

 tive parasite applies equally well in the carnation disease. 

 Since this fungus produces no spores to disseminate it in 

 the air, but is limited to growth in the soil, sterilization by 

 means of steam gives absolute results in preventing the dis- 

 ease, if healthy propagating stock is used. Another carna- 

 tion stem rot is caused by a Fusarium similar to that in the 

 chrysanthemum. In this case a soft, rapid decay does not 

 occur, as in the Rhizoctonia disease, but the fungus works 

 up through the pores of the stem, gradually clogging them, 

 and the plant slowly fades away and dies. The stem goes 

 to pieces in the last stages of the disease, but may be badly 

 affected some time before this, the first symptoms appearing 

 in the wilting of the plant. The use of healthy stock and 

 fresh or sterilized soil is to be strongly urged where this 

 disease has appeared, as well as the removal of all affected 

 plants and the soil near them from the bed. 



Aster Stem Rot. — A Fusarium stem rot of the China 

 aster is very common and destructive, and seems to be on 

 the increase. This disease will be more fully described in 

 a bulletin of this division. Our investigations have shown 

 that it is always first contracted as a "damping off" in the 

 seed bed. Some plants die at this stage, but many live to 

 be set out in the bed. Here the disease manifests itself at 

 almost any time, by a gradual wilting, fading and death of 

 the plant. Only in the last stages does the rotting of the 

 stem appear ; long before this the pores are clogged by the 

 fungus, and wilting produced as in the other diseases. So far 

 as our results go, it is possible to entirely avoid the trouble 

 by starting the plants in the open ground, or otherwise 

 avoiding "damping off" conditions. Thousands of plants 



