Annual Report f&r 1889 of the CoMBvUing. EatomolorjUt. 179 
As these clover attacks precisely agree with those which have 
been carefully and repeatedly studied by Mr. Whitehead and myself, 
with frequent reference of our observations for verification to Dr. 
Ritzenia Bos and Dr. J. G. de Man, of Middleburg, and the micro- 
scopic measurements have been checked by reference to those of 
Dr. Kuhn, Director of the Agricultural Institute, Halle, Germany 
(another leading authority on the subject), I do not think that there 
is the least ground for doubt that the attacks of clover sickness now 
specially under consideration are caused by the " stem eelworm," 
the Tykncltw devasfatrix, Kuhn ; and I mention this so particularly 
because the form of attack being now before the managers of two 
such important agricultural stations as Woburn and Kothamsted, 
they will be able to point out widely the connection of the outward 
signs of deformed growth with internal presence of the " stem eel- 
worms " which cause this " sickness," and (where microscopic ap- 
pliances and figures of Nematodes are at hand for reference) the 
Tylenchi may be identified. 1 
As, however, these little white wormlets are very small — only 
about the twenty-fourth part of an inch long when full-grown — for 
general purposes with this clover " stem sickness," as with the " Tulip- 
root " disease of oats, it is on the external appearance of the diseased 
crop that we must mainly rest for identification. 
I would venture to suggest that, as clover suffers under several 
attacks, and much uncertainty arises from the term of " sickness " 
being applied to them all, it would be a convenient and correct 
distinction to adopt the Continental term of ' stem-sickness ' where 
it is wished to particularise the attack of the Tylenclius devastatrix, 
which is more especially known as " L'anguillule de la tige," or " stem- 
eelworm." 
The best applications which have been reported to me for pre- 
venting or checking eelworm attack have been sulphate of potash, 
sulphate of ammonia, and phosphates, the first two in largest pro- 
portion ; or sulphate of potash alone, which has had excellent effect 
in checking eelworm attack when beginning to show itself. 
In the experiments on stem-sick clover at Rothamsted of which 
I was permitted to have notes, forwarded to me by Mr. John Willis, 
it was found that a mixture of sulphate of potash, 3 cwt., and 
sulphate of ammonia, 1 cwt., per acre, acted well ; as did also 
sulphate of iron applied on another plot at the rate of 2 cwt. the 
acre. These applications were given on April 3, and on examination 
on May 14 it was found that the disease had entirely ceased, and 
the clover was growing most vigorously. 
The above manurial applications extended their beneficial effects 
to the second crop. On July 26 the vigour of plant was reported as 
very marked on the plot which received the potash and ammonia 
mixture ; the growth was not so luxuriant on the plot treated with 
1 For full description of T. dernstatrlx, with life-history, and method of 
injury to various crops, together with full illustration in all stages, see 
L'angitillulc de la Tiye et les maladies des planies dues a ee Xvmatodc. Par 
Dr. J. Ritzenia Bos. 
N 2 
