P. A. VAN DEB BUL 289 



Soil once contaminated undoubtedly retains the disease germs 

 for years and the organism can only be got rid of by disinfecting the 

 soil. Thus Sturgis suggests disinfecting the beds with steam, a method 

 which as yet has not proved practicable on a large scale though 

 undoubtedly excellent for greenhouse purposes in which case the whole 

 building should be disinfected. 



The most practical method would appear to resort to crop-rotation, 

 a process which has proved itself a cleansing factor in garden economy. 

 Even if in order to practise crop-rotation it should be uecessary to 

 have additional ground, the money will be well spent, and at the end 

 will be found more profitable than placing cuttings in diseased ground. 



When once the disease is noticed prompt action is necessary. Diseased 

 plants should be immediately uprooted and destroyed ; to leave them 

 standing or to dig them in would simply mean propagating the disease. 



It has been shown that soil organisms are also spread by : (1) water 

 running from or through a higher diseased area to a healthy lower 

 area; (2) through the soil adhering to the boots of gardeners or feet 

 of animals; (3) by using tools on an infected area and, without first 

 sterilising, transferring them for use on healthy soil. 



Attempts should be made as far as practicable to prevent the disease 

 from spreading by one or any of the above methods. 



Sturgis 1 had reason for believing that the fungus may be carried 

 over in diseased cuttings. I, too, have observed instances where this 

 appears highly probable and would strongly suggest that growers 

 take cuttings only from healthy plants and lay them in in a healthy 

 soil. As far as possible, it would appear advisable for growers to grow 

 their own stock and not resort, to the, at times, objectionable process, 

 frequently accompanied by serious consequences, of obtaining cuttings 

 from their neighbours. 



Summary. 



1. The disease in the carnation here commonly referred to as 

 "Wilt" or "Crown-rot" is caused by a fungus belonging to the genus 

 Fusarium. 



2. The disease usually shows as a wet rot of the stem just below 

 the soil. The lower leaves turn a sickly colour, are usually more erect 

 and soon the whole plant is dead. 



3. This fungus was isolated from diseased carnations; grown in 



1 Sturgis, Win. C, op. cit. p. 1. 



