294 JOUENAL OF THE EOYAL HOETICULTUEAL SOCIETY. 
would contain considerably more, and in March it would be safe to add 
half as many again. 
I think the facts which have just been stated with regard to the life- 
history of this pest clearly show us that the most suitable time to apply 
a remedy for the disease would be during the winter months, or, in other 
words, from the fall of the leaf to the beginning of February, when, so far 
as we know at present, every mite is hidden away in the interior of the 
buds and the eggs are comparatively few in number. Of course this habit 
adds much to the difficulty of the treatment, and, with the exception of 
hot water and hydrocyanic acid gas, nothing has yet been discovered which 
will kill the mites without also at the same time seriously injuring or 
completely destroying the tree. 
Kinds of Currants Attacked. — All varieties of the Black Currants 
{Bibes nigrum, Lin.) are attacked, and if any preference is shown for one 
variety more than another it is the Baldwin. Miss Ormerod * also gives 
the Red Currant {B. ruhrum) and the " Tasteless Mountain Currant " 
(B. aliyinum) as additional food plants ; but, I believe, these plants have 
not been found infested in this country. I certainly have never met with 
the disease on Red Currant, although I have been informed that it does 
occur with us on this species of Bibes. 
Natural Enemies. — I have found the larvae of the Lace wing Fly 
{Chryso^a sp.) and also a species of Hover Fly (Syrpfius sp.) in the semi- 
open gall-buds. It is well known that these larvae prey upon Aphides, &c., 
but whether they were feeding upon the Phytopti I was not able to ascer- 
tain. I have also found the gall-buds tenanted by other species of Acari, 
and a number of Thrips, as I have elsewhere mentioned,t and in a 
number of buds from Toddington I have recently found numbers of 
a species of Tylenchus. 
The Efficiency of various Remedies generally adopted. 
Bemoval of Infested Buds. — The experiments at Woburn + and also 
those at Toddington § have clearly demonstrated the result of this method 
of dealing with this disease in large plantations. As regards the former, 
the Report (pp. 11, 12 I.e.) states that : "In 1896 the Baldwins showed 
signs of being attacked by the mite, and all the bushes were carefully 
examined, and all the galls removed. In spite of this, however, the in- 
festation had increased to a marked extent in the following year, and had 
spread in certain degree to the Black Naples. The galls were again 
removed in 1897, but a still further increase in the severity of the attack 
was noticed in 1898. Such observations must throw considerable doubt 
on the removal of the galls as a remedial measure, though it is frequently 
advocated. It might, it is true, succeed when assiduously followed in a 
very small plantation, but when attempted on a larger scale it seems tO' 
have but little effect. ... As further evidence we may cite the following 
cases, in which we selected five bushes of Baldwins, and counted the 
* Report of Observations of Injurious Insects, 1897, pp. 144, 145. 
f Newstead, Recent Investigations on the Currant Bud-Mite, p. 8. 
+ Second Report of the Woburn Experimental Fruit Farm, 1900, pp. 11, 12. 
§ Ormerod, Report of Observations of Injurious Insects during the Year 1897,. 
p. 150. 
