WORMS. 223 



the haulm and the ear often do not come out of the 

 leaf-sheaths ; in other plants the ear may appear, but 

 remains small and deformed as well as the rest of the 

 haulm, while the grains which develop are small. A 

 number of shoots, however, may develop normally 

 and bear fruit. Badly infested plants quickly die, 

 some at the very beginning of spring, others later. 



Where the disease is very bad it may easily be 

 recognized by its characteristic distribution. A 

 number of bare places are noticed in spring on the 

 infected fields; round about these places still living 

 but badly diseased plants may be noticed, and the 

 symptoms of attack are less obvious the further one 

 goes from the bald spots. 



On the death of the rye-plants the eelworms mostly 

 travel back to the soil, but sundry eggs and larvae 

 stop in the dried-up remains. Rye straw may further 

 iafect a diseased field by getting into farmyard 

 manure and being brought back agaia with it; for 

 the eelworms (at any rate as eggs and larvae) are 

 killed neither by drying nor by the action of dung 

 and other decaying substances. Strongly infected 

 spots (bare patches) on an infested field are usually 

 the places where dung containing diseased rye-straw 

 has lain for some time. From such centres the 

 spreading of the eelworms takes place : (1) actively 

 by the migration of the worms, (2) passively by rain, 

 the feet of labourers, the hoofs of horses, field imple- 

 ments, etc. ; also (on loose soils) by the wind, which 

 not only blows about particles of earth, but also the 

 dried-up larvae which are always found on the surface 

 of the ground. As the eelworms multiply very 

 rapidly whenever they are in the plants, and as the 

 means of distribution are very numerous, the disease 

 spreads with great rapidity. 



Bemedies. — Proper rotation; limitation of the culture 

 of rye, growing in place of it carrots, turnips, or 

 lupines. Now and then (but not too frequently). 



