3 
HOP APHIS. 
11 
swarming with Aphis from top to bottom, and there was hardly a 
green leaf to be found. 
“ On August 16th it was noted :—The Aphides have gone on in¬ 
creasing to such an extent that they have almost killed the plant. The 
top and under side are smothered with them, and the stems and all 
the interior of the muslin are full of the dead bodies of the Aphides. 
Now these Aphides must have come from the ground, for, as I stated 
before, it was simply impossible for any insect to get in.” —Arthur 
Ward, The Gardens, Stoke Edith Park, Hereford. 
In the above experiment it will be noticed that the plant was very 
carefully examined and considered clean at the time of enclosure, and 
for more than a fortnight afterwards, although subsequently the 
Aphides appeared in such numbers as nearly to smother the plant. 
This experiment seems therefore to point in this case to the Aphides 
coming up from the ground or from crevices in the stock or roots, 
where in some shape, it may be as eggs, or it may be as females hyber- 
nating, they had passed the winter. 
It would be a most serviceable thing if this experiment was tried 
in different localities. It would be no great trouble to put three 
poles over a Hop-liill, and fix stout muslin so as to stop ingress or 
egress, and, by setting up the poles early in the year before Hop Aphis 
was about, or indeed, to make quite sure, before the plants began to 
grow, there would be no need to watch to be sure of not enclosing 
Aphis on the plant. If we then found, on the authority of many 
observers, that the enclosed Hops were attacked, we should have posi¬ 
tive proof that a part at least of the attack comes up out of the ground, 
and the necessary treatment of the soil or Hop-stocks to get rid of the 
harbouring pest during its quiet state, would very shortly be made out 
by those most concerned and experienced in Hop growing. 
I may add the experiment was undertaken at my request by a 
thoroughly competent observer, in imitation of the method by which 
Prof. Riley, State Entomologist, U.S.A., discovered the missing links 
in the life of the Grape Phylloxera. 
Effects of Healthy Growth. 
The following notes refer to the effect of a healthy state of the 
plant on the non-increase of Aphides :— 
“It will be noticed that it is not the point of the healthy Hop 
growing past attack, which attention is specially drawn to here, 
but that in certain states of sap the Aphides do not increase. This 
exemption from attack has often been noticed, sometimes in one 
special locality (as I believe is often the case in the Isle of Tlianet), 
sometimes in the case of what is known as a “ lucky ” ground or part 
of a ground, or in the lesser instances of a few hills or a single one. 
