44 



luvestiyatloit of Bulb Rot of Xarcissas 



if they exist, are obviously less definite than those which differentiate 

 the biologic forms of the Uredineae and of the Erysiphaceae. 



If the eelworm of Narcissus follows the behaviour described by 

 Hitzcnia Bos for that of the hyacinth and of the onion it is clear that 

 while the bulbs are in the ground there is very little fear that it will 

 migrate to neighbouring weeds. However, diiectly the bulbs are lifted 

 any eelworms remaining in the ground are likely to migrate to suitable 

 weeds^ which thus would become valuable traps. It is desirable, 

 therefore, that before replanting the ground all weeds should be removed 

 and burnt ; weeds should never be allowed to wilt on the soil nor should 

 they be dug in. 



A list of the more common British weeds and cultivated plants 

 which have been described as affording shelter to Tylenchus devastatrix 

 is given here. It is compiled from papers of Ritzema Bos (2,3); it has 

 no claim to completeness. 



Medicago sativa 



Trifolium pratense 



Polygonum fagopyrum 

 „ convolvulus 



„ persicaria 



„ lapathifolium 



Bellis perennis 



Ranunculus acris 



Geranium molle 



Sonchus oleraceus 



Myosotis stricta 



Plantago lanceolata 



Poa annua 



Holcus lanatns 



Brassica rapa 



Anthoxanthum odoratum 



Centaurea jacea 

 ,, cyanus 



Spergula arvensis 



Allium cepa 



,, proliferum 

 vineale 



Hyacinthus romanus 

 ,, orientalis 



,, precox 



Tulipa gesneriana 



Lilium candidum 



Fritillaria imperialis 



Galtonia candicans 



Scilla sibirica 

 „ campanulata 

 ,, cernua 



Narcissus Tazetta 



,, Pseudo-narcissus 



Muscaria botryoides 

 ,, comosum 



Huniulus lupulus 



Phlox 



Chelone glabra 



Solanum tuberosum 



Wheat 



Rye 



Oats 



Vicia Faba 



,, schoenoprasum 

 ■1 The question of the occurrence of migration and its extent would be well worth 



investigation. 



