EELWORMS 555 



continue for months before the tree eventually dies. On the 

 other hand, in the case of trees from four to six years old, 

 having an abundance of healthy, dark-green foliage, and 

 laden with berries, no preliminary symptoms foreshadow 

 the end, which is sudden. The tap-root suffers most, 

 becoming much swollen and barrel-shaped, and covered with 

 much thickened, rugged bark, sodden with water. The cork- 

 cells of the bark become sac-like and much elongated 

 radially, resembling the palisade tissue of a leaf. The 

 eelworms are present in numbers in spaces between these 

 abnormal cork-cells. 



The smaller roots usually also bear a number of knots or 

 galls containing eelworms. 



Diseased trees show up very conspicuously, and the disease 

 gradually extends from a centre as fresh trees are attacked. 

 So far as experience goes, when a tree is once attacked it 

 never recovers, hence diseased trees should be removed on 

 the first indication of disease. 



Treating the soil with bisulphide of carbon is the most 

 certain remedy. This should be applied when diseased trees 

 have been removed, and the treatment should extend well 

 beyond the area of diseased trees. 



Noack, Fritz von, Zeitschr. Pflanzenkr., 8, p. 137. 



Clover sickness. This is a general term which covers 

 more than one specific disease of clover. The clover sickness 

 caused by a fungus has been already described. In the 

 present instance the injury is caused by an eelworm (Tylenchus 

 devastatrix}. The symptoms are a yellowing and gradual 

 dying down of the clover, usually in patches which gradually 

 extend in area. If the injury is actually caused by eelworm, 

 the branches of affected plants will be found to be much 

 swollen and spongy in texture, and microscopic examination 

 will reveal the presence of eelworms and their eggs in the 

 swollen tissue. If diseased plants are allowed to decay on 

 the land the eelworms pass into the soil and endanger future 

 crops. When the diseased patches are small, it is wise to 

 remove all the plants and burn them, afterwards dressing the 

 land with sulphate of potash, at the rate of 4 cwt. per acre. 



'Tulip-root' or 'Segging' of oats. This disease is caused 

 by Tylenchus devastatrix. The symptoms are the swollen 

 appearance of the base of the stem, which is usually sur- 



