166 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



If the leaves come up when all the roots have been eaten, then the leaves 

 will turn brown at the tips and make very little growth. They then look 

 much like the leaves of a bulb attacked by basal rot. The cases where 

 the leaves show yellow-stripe on the margin of the area of destruction 

 seem to be those where parts only of the roots have been eaten by the 

 caterpillars. 



I think, therefore, that the various methods of accounting for the 

 yellow-stripe suggested by the writers I have cited, excepting that of cold, 

 are not applicable to the cases I have mentioned in my own garden, but 

 I by no means wish to suggest that they may not be perfectly accurate in 

 the particular instances which were in the minds of the writers. 



The observations of the writers I have cited and my own may be 

 satisfactorily reconciled if we admit that yellow-stripe is a symptom, and 

 not a specific disease, and that it may occur as a consequence of unsuit- 

 able condition of the soil, or inclement weather at a critical stage in the 

 growth of the plant, or sometimes of physical injury to the bulb or its 

 roots. Subject to additional and more accurate observation, I think it 

 impossible to go further at present. 



The conclusion is unsatisfactory in one sense — namely, that it does not 

 enable one, on seeing the occurrence of an outbreak, at once to apply a 

 remedy. We must go further and inquire what is the unsuitable con- 

 dition to which the plant has been subjected. But if correct, the conclu- 

 sion has also a satisfactory side, for we need not at once dig up and 

 discard the affected plants (as is desirable, for instance, in the case of 

 basal rot), but we may hope by altering the conditions of growth, or (if 

 the weather be at fault), in a more favourable season, to find the bulbs 

 recover and again become satisfactory plants. 



I venture to sum up my observations of the occurrence of yellow-stripe 

 as follows : 



1. It is a phenomenon comparatively recently noticed. 



2. It is confined to a few garden varieties of Narcissus. 



8. It seems connected with debility in the plant, the leaves are less 

 robust than usual and decay earlier than those of healthy plants. In a 

 bad case the bulbs refuse to flower at all. 



4. The origin of the phenomenon has been assigned by growers of 

 experience to a great variety of causes. 



5. It is more prevalent in some years than in others, and plants badly 

 affected one year may show complete recovery the next year. 



(). It is not accompanied by discoloration of the bulb or any apparent 

 fungoid growth. 



7. It does not appear to be infectious. 



8. In particular cases both cold and partial destruction of the roots 

 seem probable explanations of the phenomenon. 



