12 



MASS. EXPERIMENT STATION BULLETIN 427 



White (75) found that 42 percent of the cuttings from a bed containing diseased 

 plants were contaminated with fungi of which 7 percent were Verticilliuni cine- 

 rescens Wr., the cause of a serious wilt disease of carnations in England. In 

 another instance 22 percent of the cuttings yielded organisms associated with 

 carnation wilt diseases, 38 percent yielded organisms not suspected of causing 

 wilt, and 40 percent of the cuttings were clean. The carry-over of the Verticillium 

 wilt fungus occurs mainly when the cuttings are taken adjacent to visibly diseased 

 areas, but in practice some cuttings are infected even when precautions are 

 taken to avoid the neighborhood of diseased areas (77, 78). The fungus was 

 isolated from parts of shoots well beyond the limits of any microscopically 

 visible internal or external symptoms. Wickens (78) isolated Fusarium dianthi 

 freely from branches which externally appeared perfectly sound, but only within 

 the limits of some alteration in the conducting tissue. Bickerton (5) obtained 

 the branch rot fungus from ofT-colored, and frequently from green cuttings from 

 apparently healthy plants growing adjacent to diseased plants. Sometimes the 

 fungus was found in the shoots of infected plants even in the absence of any 

 visible discolorations of the vascular tissue. Sturgis (65) felt that the outbreak 

 of the disease in his experiments was due to the presence of the fungus in the 

 tissues of the original cuttings. 



In the Boston area serious losses from the Fusarium root rot organism have 

 been observed in the propagating house and among young rooted plants in flats 

 or beds in the early months of the year. The axils of the flowering branches from 

 which cuttings are taken provide collecting places and reservoirs for water. 

 Water is a carrier of fungous spores and thus it is not uncommon to note discolored 

 infected tissue at the nodes. The Alternaria blight fungus and the Fusarium root 

 rot fungus are frequently found associated with discolored or decayed tissue at 

 the nodes of the branches. A basal decay of the cuttings follows when cuttings 

 from such sources are planted in sand. The snag in the branch or the point 



Table 2. Results of Tissue Transfers From Carnation 

 Cuttings to Artificial Culture Media. 



