34 Potato Disease and Allied Diseases [CH. 
disease from one season to another. The fungus does not 
attack the bulbs but prevents the leaves from carrying 
on their normal functions of manufacturing food stuff 
and so the bulbs are smaller. 
Fig. 11. Conidiophore and conidia of Peronospora schleideni 
which causes onion mildew. (Magnified.) (After Massee.) 
Remedial Measures. 
Well-drained land does not suffer so much as wet 
land. Onions should not be planted on land which 
had a diseased crop of onions in the previous season. 
