42 



Investigation of Bulb Rot of Narcissus 



areas (Fig. 4). Owing to the large number of eelworms in such bulbs 

 it usually happens that the disease spreads quickly, thus separating 

 the scales from the plate ; such plates bearing only roots are often 

 found in beds in which the bulbs are very badly attacked. It seems 

 piobable that in these cases the disease has started in the previous 

 year. 



Fig. 5. Early growth of diseased bulb. August. 



General Considerations. 



Eelworm is well known in Europe because of the destruction it 

 causes to various cultivated crops, especially to rye, hyacinth and 

 onion. 



Kuhn(5,()) in 1867 and 1868 described a disease in rye and showed 

 that it was due to the action of an eelworm, Anguillula devastatrix. 



In 1881 Prillieux(iO) investigated the "ring" disease of hyacinths 

 and attributed it to an eelworm, Tylenchus hyacintki. Two years 

 later the onion disease was shown by Beyerinck(i) to be due to Tylenchus 



Alia. 



