224 ZOOLOGY. 



potatoes, buckwheat, clover, and oats may be culti- 

 vated in the fields affected, at any rate before sowing 

 rye again. Abundant manuring, especially with 

 sulphates of potash, ammonia, and iron. Deep culti- 

 vation of the soil, since the eelworms find no food in 

 the deeper, damper layers of the soil, nor can they 

 pass into the dried condition, and so must die. 



Oats suffer from eelworms just in the same way 

 as rye. 



Clover Sickness is marked by short stunted shoots, 

 and whitish rounded buds, often remaining closed; 

 also by the whitish colour and abnormal thickening 

 o£ the shoots and buds. 



Eelworm Disease of Potatoes. — Crumpling and small 

 growth of the parts above ground. In many cases 

 there may even be no potatoes at all, or only small 

 ones, poor in starch, though sometimes they may be 

 tolerably large. On the surface of the tubers there 

 are discoloured rotten spots, not penetrating deeply, 

 and usually (but not always) at the attached end. 

 These dark patches contain the eelworms. 



Eelworm Disease of Buckwheat. — Joints of the stem 

 for the most part much thickened, but abnormally 

 short. In many cases a large amount of branching 

 in the lower part of the stem, usually at a place where 

 it bears a nodular swelling. Branches generally short. 

 There may be twists and bends in the stem and 

 branches. Often, but not always, the formation of 

 flowers and fruit is stopped. The thickened parts 

 of the stem are brittle ; they contain the eelworms 

 in their interior. 



The Wheat Eelworm 



(Tylenchus scandens = T. tritici). 



Length of the male about one-twelfth of an inch, of 

 the female one-tenth to one-fifth of an inch (according 

 to the size of the galls in which the eelworms develop). 

 The wheat eelworm is the cause of " ear cockles," also 



