200 DISEASES OF FIELD & GARDEN CROPS. [CH. 



than after other crops. We think the fact of straw from 

 stables being so frequently thrown over old clover fields a 

 sufficient explanation of this fact. Wheat after clover is 

 certainly a favourite alternation of crops with many 

 farmers, perhaps because the old decaying clover roots 

 act as good manure for the corn. When clover precedes 

 corn it should be heavily folded with sheep, and straw 

 from stables should not be used as manure. 



It is now generally accepted as a fact amongst practical 

 men that after dressing the land with farmyard manure 

 and nitrate of soda, mildew often puts in a strong appear- 

 ance ; but after mineral manures, bone superphosphate, 

 and bone meal drilled with the seed, rust and mildew are 

 much less apparent. There can be no doubt that farm- 

 yard manure has a tendency to produce a gross soft growth 

 in corn which is suitable for fungi, and that mineral 

 manures, on the contrary, have a tendency to produce a 

 firm stiff growth unsuited for rust and mildew. As corn 

 generally does so well in dry limestone and chalky dis- 

 tricts, a hint might be derived from this fact as to the 

 desirability, where possible, of manuring land with chalk. 

 We have seen this done with success in North Herts and 

 South Bedfordshire, where chalk is easily obtainable. 



It is probable that the resting -spores of the fungus 

 of corn mildew seldom hibernate through two seasons ; 

 therefore, in instances where stable manure must be used, 

 it should if possible be used in the crop preceding the corn 

 or the crop following it rather than for the corn itself. 



An alternation of crops is in every way desirable. 

 Beans, peas, turnips, potatoes, clover, and other farm pro- 

 duce should be taken alternately with corn. 



There is but one way of getting rid of corn mildew, 

 and that is certainly not by cutting down barberry bushes 

 and pulling up borage plants. Corn mildew is a heredit- 

 ary disease, and therefore no seed corn should be gathered 

 from mildewed plants. If the hereditary nature of the 

 disease is disputed, it cannot be disputed that certain 



