THE HOP FLEA-BEETLE. 85 
For use against this species in its occurrence on field and garden 
crops in Washington State, Messrs. Piper and Doane have advised 
Paris green. The former states that he obtained excellent results by 
using Paris green liberally but that it is necessary in the treatment of 
young plants to apply the remedy as soon as attack by the beetles is 
noticed. Both the wet and the dry methods are advised, as well as 
the addition of Bordeaux mixture. 
Other arsenicals. — Other arsenicals advised in such cases are arsen- 
ite of lime with soda, a which has the merit of being as effective as 
Paris green and lime and far cheaper, and Scheele's green, which is 
similar to Paris green and is employed in the same manner. 6 
SUMMARY ON THE USE OF ARSENICALS. 
To sum up the directions for the use of arsenicals, it should be 
stated that arsenate of lead should take first place because it can 
be purchased already combined in paste form, and especially because 
it contains a smaller percentage of free arsenic (60 to 70 per cent), 
and is therefore less likely to produce scorching or burning; and, 
moreover, being adhesive, it remains on the plant longer. 
Paris green, when combined with lime and water, or with Bor- 
deaux mixture, is almost equally as good as arsenate of lead, and 
is more readily obtainable in most markets, the ingredients being 
purchasable practically anywhere. It is quicker in action, but not 
so adhesive. 
The number of sprayings will naturally depend upon the locality 
and seasonal conditions; possibly it may be necessary to spray every 
few days when the plants are quite young and the beetles are most 
abundant. Later there should be longer intervals between sprayings. 
Dry mixtures are as a rule not in the same class with the sprays, 
as they can not be applied so economically, do not so thoroughly 
cover or adhere so closely to the leafage, and are more apt to cause 
burning to delicate foliage. Dry Paris green mixed with air-slaked 
lime in the proportion of about 1 part of Paris green to 10 or "20 
of lime is sometimes used, but is less effective, and frequently much 
of the material is wasted in applying it. 
The spraying apparatus used in the hopvards of British Columbia 
is shown in Plate V and figure 18, the second illustration showing a 
crew spraying hops through the rows. 
CONTACT SPRAYS. 
Among the contact sprays tried during 1008 were whale-oil soap. 
1 pound of soap to 10 gallons of water; kerosene emulsion, ] pound 
" Prepared in accordance with instructions in Farmers' Bulletin No. in:;. v . 37. 
6 Discussed in the publication quoted, as also in Farmers' Bulletin No. 127. 
