STKM EELWORM. 



213 



attack; Buck-wheat also suffers ; and in Holland both 

 Onions and Hyacinths suffer much from the infes- 

 tation ; Potatoes also are liable to the attack. Amongst 

 common meadow or field weeds, also liable to infestation 

 of this Stem Eelworm, are the Daisy, the common 

 Buttercup, the Pvibwort-Plantain, Sowthistle, Shep- 

 herd's Cress, &c. ; and amongst grasses, the Annual 



Fig. 156. — Stem Eelworm (Ti/lencliusdevastatrix) ; anterior portion 

 of female showing mouth-spear ; and embryo in ej^'^' ; all greatly 

 magnified (anterior portion mag. 440 tunes). From figures by Dr. J. 

 Ritzema Bos. 



Poa, the Meadow Soft-grass, and the Sweet Vernal- 

 grass. 



In various kinds of Eelworm attack, and especially 

 in some kinds of infestation by Stem Eelworms, the 

 presence of the pest may be known by the ordinary 

 growth of the stem, or shoot, or buds, being altered 

 into a form so definitely characterised that this 

 peculiar growth ma}^ be taken as a j^roo/" of the Eel- 

 worm being within, and the attack is often named from 

 the appearance of the diseased growth. Thus Oat 

 attack is known as "Tulip-root" (see Fig. 159, p. 216), 



