CONTENTS 



Page 



Introduction 3 



Classification of carnation wilt diseases in Massachusetts 3 



Spot, blight, and canker 4 



History ^ . 4 



Species of Alternaria and Macrosporium on the Caryophyllaceae.-. 6 



Root and crown rot.... 6 



Branch rot or Fusarium wilt 6 



Stem rot . 7 



Temperature relations of the pathogenes causing wilt 7 



Infection _ 8 



Alternaria spot, blight, and canker 8 



Fusarium root and crown rot . :.. 9 



Fusarium branch rot 10 



Rhizoctonia stem rot 11 



Stock plants and the selection of cuttings 11 



Preparation and disinfection of cuttings 13 



Trimming 13 



Soaking cuttings in water 13 



Disinfecting chemicals... : 14 



Action on fungous spores 14 



Effect on rooting and disease control 16 



Hormone materials.. 19 



Propagation..... — 21 



Sanitation , 21 



Treatment of sand 22 



Age of plants in relation to disease and yield . 23 



Fielding and benching.... 23 



Continuous greenhouse culture 24 



Segregation of young stock... _. 24 



Greenhouse management... 25 



Water syringing and naphthalene fumigation 40 



Disease resistance 42 



Alternaria spot, blight, and canker 43 



Fusarium root and crown rot 46 



Fusarium branch rot . 47 . 



Rhizoctonia stem rot 48 



Soil sterilization i 48 



Control of Alternaria blight with fungicides 51 



Toxicity of chemicals to conidia 51 



Laboratory' experiments 52 



Field experiments 54 



Discussion and recommendations 57 



Sanitation between plantings in the greenhouse 58 



Summary 59 



Literature cited 61 



