EELWORM GALLS 
107 
Aphelenchus Ormerodis Ritz. Bos, also on Strawberries. 
Hererodera radicicola Greeff, on Cucumbers, Tomatoes, 
Beet, and Clover. 
Heterodeva Schachtii Schmidt, on Beet, Hops, and various 
Crucifers. 
Tylenchus Davainii Bastian, on Mosses. 
Tylenchus devcistatrix Kiihn, on Rye, Beans, Oats, Wheat, 
Clover, Hops, and Hyacinths. 
Tylenchus fucicola De Man, on Algae. 
Tylenchus graminis Hardy, on Grasses. 
Tylenchus millefolii F. Low, on Milfoil. 
Tylenchus tritici RofTredi, on Grasses and Wheat. 
Aphelenchus fragariae causes remarkable enlargement and 
fasciation of the stems of the Strawberry; the entire plant 
is sometimes modified, and resembles a cauliflower. The 
leaves are more or less deformed, usually with one lobe 
instead of three. The worms swarm in the tissues, and 
may be found from April to September. 
Aphelenchus Ormerodis also attacks the Strawberry, giving 
rise to galls which superficially resemble those caused by 
A. fragariae, but the affected stems are white, the leaves 
yellowish, and the worms live between the sheath and the 
stem. 
Heterodera radicicola causes nodular swellings on the stem 
of the Common Couch Grass, also on Swede, Tomato, 
Cucumber, and other cultivated plants. Miss Ormerod first 
reported the occurrence of this pest, known as the “ root- 
knot ” eelworm, in Britain. It causes swellings or “knots” 
up to 6 mm. in diameter on the rootlets, and larger hyper¬ 
trophies on the thicker roots. 
Heterodera Schachtii causes lateral swellings on the slender 
root-fibres of the Cabbage, Turnip, and Charlock, and also 
does much damage to Beet. Its life-history has been investi¬ 
gated by Kiihn. The female may be found attached to the 
rootlets. At her death 300 or more ova are liberated, which 
at once attack neighbouring rootlets, and give rise to nodular 
swellings thereon. 
