CARNATION WILT DISEASES 



47 



caryophyllus L. although other Dianthus species, not named, are reported to be 

 quite resistant. Numerous species of Fusarium, further divisible into several 

 strains, exist to complicate the problem. The disease appears almost always in 

 devastating proportions in commercial houses in the summer months under the 

 influence of conditions not easily duplicated in experimental trials. Propagation 

 from diseased stock plants definitely causes the continuity of the disease. 



Fusarium Branch Rot 



- Bickerton (5) stated that resistant varieties should be grown in preference to 

 the more susceptible kinds. He determined the degree of susceptibility of 10 

 varieties of carnations to Fusarium dianthi from field observations and root 

 inoculation studies as follows: 



SLIGHT 

 King Cardinal 

 Maine Sunshine 

 Patrician 

 Peter Fisher 

 Puritan 



MODERATE 

 Sophelia 

 Virginia 



SEVERE 

 Chief Kokomo 

 My Love 

 Spectrum Supreme 



The reaction of many varieties to the fungus was determined by the same 

 method; namely, dipping the rooted base of carnation cuttings as they are taken 

 from the sand in sterile water containing pure culture inoculum of the fungus 

 and then growing the plants in steam-sterilized soil. Extreme reactions to the 

 fungus were manifested by different varieties, as, for example: 



VERY RESISTANT 

 Dorothy Napier 

 Eleanor 



Elizabeth Rowe 

 Georgina 

 Hazel Draper 

 Helen Hussey 

 John Briry 

 Maine Sunshine 

 Miller's Yellow 

 Mrs. C. B. Johnson 

 Puritan 

 Tom Knipe 

 Woburn (Figure 12) 



VERY SUSCEPTIBLE 

 Barbara Brigham 

 Joan Marie 



Marchioness of Headfort 

 Mary Stuart 

 New Deal Ward 

 Nina Brener 

 Northland 

 Pelargonium 

 Peter Fisher (regular) 

 Pink Lady (Virginia Rose) 

 Pink Treasure 

 Rosalie 

 Scarlet King 

 Spectrum Supreme 

 Virginia (regular) (Figure 12) 

 Wildfire 



In general, these varieties show a similar performance in commercial culture 



Further study is required to determine more definitely the susceptibility of the 

 varieties to branch rot under variable conditions. Disagreement with the results 

 reported by others might readily be due to the influence of variable genetic 

 strains of the fungus. The analysis and segregation of the progeny resulting 

 from selfing and hybridizing very resistant carnations and the development of 

 commercially desirable types resistant to the branch rot fungus represent a 

 promising field of study. 



