210 
Hup Cultivation. 
Earthing. 
Earthing, or putting earth over the stocks between the poles, 
is done by placing four or five shovels of fine earth over them in 
June to keep the bines in their places and to ensure a growth of 
roots for cuttings, or sets. It also stops the extraneous growth 
of bines from the stocks, which would exhaust them, and keeps 
them in their places. 
Washing for Aphis Blight. 
This has become in recent years almost a necessary opera- 
tion, as the “ hop fly,” or aphis, known by the systematic name 
of Pliorodon humuli, makes its appearance every season. This 
aphis, called by Lance “ the barometer of poverty,” 1 before 
methods of preventing its increase were discovered, often 
changed in a few weeks the appearance of the whole of the 
plantations, from the prospect of a bounteous crop to the black- 
ness of utter blight. For instance, in 1823, the aphides were so 
persistent that, only 1 cwt. 1 qr. 5 lb. were grown per acre. 
In 1825, the worst attack on record, only 1 cwt. 8 lb. were 
yielded per acre. 
Until 1860 there were no means known, in any degree 
efficacious, of checking the progress of these aphides, and the 
planters bore the periodic inflictions without seriously attempting 
to avert them. The practice of washing or spraying the plants 
with insecticides, or insectifuges, was introduced about twenty- 
eight years ago, and it is now regularly adopted by planters as 
soon as there are signs of blight. It has been found by ex- 
perience that directly aphides are seen on the plants, washing 
should be at once commenced, because of their extraordinary 
power of reproduction described by Professor Owen as follows : — 
The first formed larva of early spring procreates not one, but eight 
larvae like itself in successive broods, and each of these larvce repeats the 
process ; and it may be again repeated in the same geometrical ratio until a 
number which figures only can indicate and language almost fails to express 
is the result . 2 
If the aphides once get ahead, it is most difficult to clear them 
off, and at the same time the plants have lost sap and become 
unhealthy from their action. Spraying, or washing, as it is gene- 
rally called, must be repeated again and again, if fresh aphides 
appear. During the last three or four years, some planters have 
washed their hop plants all over three and even four or five times 
in the same season. This entails an expense of at least 21. per acre 
1 The Hop Farmer. By J. Lance, 1838. 
* Owen. On Parthenogenesis. Van Voorst : London, 1849. 
