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VEGETABLE GROWING IN NEW SOUTH WALES. 



The parasite is confined either to the soil or to the underground parts of 

 the plant, and therefore sprayings of any kind are of no use against this 

 disease. The majority of Crucifene are susceptible, but it appears that 

 varieties of cabbage vary in their susceptibility. Soils of an acid nature are 



Club-root of Cabbage. 



(Plasmodiophora brassicce.) 

 Photo by Bureau of Microbiology. 



favourable to the development of the parasite. Lime is the most valuable 

 substance to use to check it. Applications of two to four tons per acre are 

 recommended, after all refuse of diseased crops have been removed and 

 burnt not buried. Seedlings, should be carefully examined, and, if they 

 show any signs of club-root, should be burnt. As the soil may remain con- 

 taminated for some time after the crop is attacked, a rotation of crops (see 

 page 22) should be carried out. 



" Curly Top " of Sweet Potato. 



This disease shows itself in the early stages of the growth of the plant, 

 generally in isolated plants throughout the crop. Minute tubercles, which are 

 at first the same colour as the leaf, are produced on both sides of the leaves and 

 on tine stems and roots. Later, the leaves turn black arid the whole plant wilts. 



