CONTRIBUTIONS FROM THE WISLEY LABORATORY. 65 
CONTRIBUTIONS FROM THE WISLEY LABORATORY. 
XXXI. — Experiments on the Control of Eelworm 
Disease of Narcissus. 
By J. K. Ramsbottom. 
Historical Review of Treatments previously Applied. 
In 1912-13 Mr. R. T. Hewitt carried out a series of experiments on 
the control of the Narcissus Disease, and, although his work was by no 
means completed, he recommended the soaking of affected bulbs in a 
cold solution of copper sulphate at a strength of from 5 per cent, to 
y\ per cent, for a period of 17 hours. The effect of these solutions 
on the bulb, after soaking for the length of time stated, is recorded as 
being slightly injurious, and live eelworms were to be found in the 
centre of affected bulbs after treatment. A similar result was obtained 
by soaking the bulbs in a 10 per cent, solution of copper sulphate for 
7 hours, while soaked in the same strength of solution for 24 hours no 
live eelworms were discovered in the treated bulbs. The bulbs, how- 
ever, were badly injured by this strength of solution and therefore did 
not admit of this treatment being recommended. Mr. Hewitt also 
soaked bulbs in cold solutions of formalin 5 per cent., for 2 and 5 hours ; 
formalin 10 per cent., for 1 and 2 hours ; cresylic acid 2 per cent., for 
I and 2 hours ; and paraffin for \ and 1 hour ; but in no case did the 
treatment kill the eelworms in the centre of the bulb. 
The same writer conducted a few experiments with warm water 
at a temperature of I20°F., and records that all the eelworms are 
killed in bulbs soaked in water for 1, 2, and 6 hours at this temperature ; 
the bulbs were killed even at the end of one hour by this process. Mr. 
J. W. Barr has also experimented with the warm-water treatment, 
and in the course of the discussion of my lecture (herewith published) 
he informed the audience that he had obtained excellent results by 
soaking infested bulbs in water at a temperature of no° F. for a period 
of one hour. 
Effect of Chemicals upon Tylenchus devastatrix. 
Last August experiments were commenced with a view of finding 
some chemical method of controlling the eelworm attack on Narcissus 
bulbs. The first series of experiments was designed to test the effect of 
various chemical solutions and gases upon the eelworms by placing the 
worms in direct contact with the solution or gas. Where solutions 
were employed, the eelworms were placed in watch-glasses containing 
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