HOW TO GROW GOOD CORN. 181 



6. Puccinia fabce — Bean-rust. 



7. jEcidium berberidis — Barberry-rust. 



8. Cladosporium herbarum — Corn-ear mould. 



9. Botrytis in/estans — Potato-mould and mildew. 



10. Botrytis — Turnip-mildew. 



11. Oidium erysiphioides ) 



12. Brysiphe macularis j ^ 



13. Oidium aborlifaciens — Ergot of grasses. 



1. TJredo segetum, Sinut or Dust-brand, is common 

 to barley, and not unfrequent in wheat ; in both of 

 which crops it is easily recognised from the affected 

 ears of corn appearing as though they had been pow- 

 dered over from the sweep's soot-bag. On closely 

 examining these blackened ears, we find that the 

 whole flower has, as it were, effloresced into a black 

 powder, which, on being placed under the microscope, 

 is shown to be composed of myriads of granules, called 

 by the fungologist spores, in which latter are con- 

 tained still smaller grains, or sporidia. 



These black spores are all washed away by the time 

 the crop is ripe, leaving the stalks bare and grainless, 

 so that the sample suffers no injury from this blight, 

 which, even if present after threshing, would only 

 tend to a slight discoloration of the sample, which is 

 remediable by the smutter. Its chief effect, however, 

 consists in causing the loss of much grain. We have 

 observed it to the extent of as much as an eighth, but 

 usually the diminution is about equal to the amount 

 of seed sown ; though it is not improbable that the 

 whole crop may in many cases be greater when the 

 smut is present. Sheep-folding previous to barley, 

 special manuring for this crop, and other causes of 

 increased fertility, are constant causes of the increase 

 of the dust-brand. 



