MYXOGASTRES 



525 



alkali is decidedly detrimental to its development, and as 

 the use of acid manures is very general at the present day, 

 it will be seen that much more land is rendered favourable 

 for the development of Plasmodiophora than in bygone 

 times. 



Lime is the best and most practical preventive of finger- 



FiG. 156. Plasmodiophora brassicae, causing finger-and-toe 

 of root of Brussels-sprout. 



and-toe known; from five to seven tons per acre, to be 

 applied in the autumn, either six months or eighteen months 

 before the turnips are sown. A second method, also recom- 

 mended, is to apply the lime immediately after a diseased 

 crop of turnips is removed; about two tons will suffice if it is 

 spread evenly over the land. Such a dressing will produce 

 no visible effect on finger-and-toe until the next crop of 

 turnips is grown, but it may prove to be of value to interven- 

 ing crops. 



It is important to bear in mind that plants can, as a rule, 



