JOURNAL 



OF THE 



Royal Horticultural Society. 



Vol. XXXIV. 1908. 

 Part II. 



YELLOW-STRIPE IN DAFFODILS. 

 By H. R. Darlington, F.R.H.S. 

 [Lecture delivered June 9, 1908.] 



Daffodil growers have long boasted of the immunity their favourites 

 enjoy from the attacks both of disease and insect enemies. The late 

 Mr. Burbidge wrote : " Fortunately the Narcissus is in most cases 

 sufficiently vigorous in constitution to ward off those agents of decay 

 which are common to plants of a more delicate character, and it is 

 probable that their poisonous qualities protect them from the ravages of 

 many insects, just as they escape being eaten by cattle from the same 

 cause. Even mice, which are so fond of the Crocus, never attack Narcissus 

 bulbs." Mr. Kirby, in his book on daffodils, heads a chapter, " The One 

 Insect and the One Disease," referring to the daffodil fly and basal rot. 



It almost seems that the modern daffodil is losing this immunity. 

 I have myself recently called attention to the destruction wrought in 

 daffodil beds by a caterpillar, afterwards identified as that of the common 

 Swift Moth, from which I have, to my regret, again suffered this year ; 

 while the occurrence of yellow-stripe in certain varieties of daffodil is now 

 becoming sufficiently common to render it desirable to make such inquiry 

 into its cause as may be practicable, and, if it be possible, to find a 

 remedy. 



"Yellow-stripe " shows itself in a mild case as a scarcely perceptible 

 discoloration or yellowing of the veins of the leaves, and may then have 

 little noticeable effect on the flowering or health of the plant. In a more 

 serious case distinct bands of yellow are seen running lengthways up the 

 leaves ; the flowering becomes weaker, the petals deficient in substance 

 and colour, and both leaves and flowers fade prematurely. In a very bad 

 case, no flowers at all will be produced, and the leaves are heavily streaked 

 with yellow and wither and fade before they fully develop. 



The yellow stripe may run the whole length of the leaf, but does not 

 generally do so, except in a bad case, when the leaf is often curved or 



vol. xxxiv. M 



