THE HOP FLEA-BEETLE. 85 



For use a^fainst this species in its occurrence on field and garden 

 crops in AVashinfjton State, Messrs. Piper and Doano 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," which has the merit of being as effective as 

 Paris green and lime and far cheaper, and Scheele's green, w'hich is 

 similar to Paris green and is employed in the same manner.* 



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 the}^ 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 fjreen 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 nuich 

 of the material is wasted in applying it. 



The spraying apparatus used in the hopyards 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 lOOS were whale-oil soap, 

 1 pound of soap to 10 gallons of water; kerosene emulsion, \ pound 



" Prepared iu accordance with instructions in Farmers' Bulletin No. 283, p. 37. 

 * Discussed in the publication quoted, as also iu Farmers' Bulletin No. 127. 



