82 



EELWOKMS. 



destroyed in this way every year. In wheat it may cause the 

 same appearance. Peas and beans are infested in the stems, 

 which decay. Onions also become swollen and contorted. The 

 female produces oval eggs, which occur, together with larvae and 

 adults, in the plant tissue. The larvse on hatching are about 

 one-seventh the size of the adults. As they grow they moult 

 their skin. As the plants decay they pass into the soil, where 





Fio. 32. — The Stem Eelworm {Tylcnclms devi'Mati-ix. Eutiu). 



1. Eelworm. 2. Young form just emerged from egg. 3. Eelworm and egg in 

 plant tissues. (1 mucll magnified, 2 and 3 more highly magnified.) 



they can remain a long time, even when dried up for some 

 months : moisture resuscitates them. They are also carried in 

 the straw in manure. Spring-sown corn is attacked mostly ; 

 autumn-sown seldom suffers. Thus, where this disease is bad, 

 spring-sown corn should be given up. Deep ploughing with a 

 skim-coulter should follow an attack, and such plants as barley 

 grown afterwards. Top-dressings will also sometimes save an 

 attacked crop if given in time. 



