LIFE HISTORY AND CONTROL OF HOP FLEA-BEETLE. 53 
number present in such places is sufficient to warrant their destruc- 
tion, two hundred or more of these should be gathered, the beetles 
counted, and the average number of beetles per hill determined. If 
the number of beetles found will warrant the expense, the vine-stubs 
and string-pegs should be gathered during the cold weather and 
burned. In case the temperature is above 40° F. the stubs and pegs 
should be collected into tarred buckets to prevent any beetles from 
escaping. Below 40° the beetles are inactive and this precaution is 
unnecessary. 
BORDEAUX MIXTURE. 
Bordeaux mixture has long been recommended as a deterrent 
against flea-beetles, and, should the overwintering adults severely 
attack the young hop-shoots, may prove quite effective against the 
hop flea-beetle. During the spring of 1909, when the hops were 
coming out of the ground, an infested region was thoroughly sprayed 
with the 5-5-50 formula, several rows being left as checks. Unfor- 
tunately wet weather followed, which, while it favored the growth of 
the hops, held the beetles back so that no definite conclusions could be 
drawn. 
The Agassiz hopyards, at the time that the beetles became numer- 
ous, Avere sprayed with the same formula. The Bordeaux mixture 
certainty deterred the beetles, but drove them to the growing tips, 
where they seriously damaged the terminal bud. This destruction of 
the terminal bud is very undesirable, as it causes the plant to force 
out arms close to the ground. Besides driving the beetles to the grow-, 
ing tips, the Bordeaux mixture burned the tender buds and also 
those leaves that were badly chewed by the beetles. Much damage 
was done in this way. 
Since it was evident that the 5-5-50 formula was too strong, a 
series of experiments was conducted to determine the relative effect- 
iveness of the 5-5-50, the 2^-10-50 Bordeaux mixture, and straight 
slaked lime, 15 pounds to the 50 gallons, as deterrents. Two-thirds 
of each vine chosen for this experiment was thoroughly sprayed with 
the various materials. A cloth cage was placed over each one, and a 
large number of flea-beetles were liberated inside. Five days after 
setting these experiments it was observed that, although the sprayed 
portions were slightly eaten, the unsprayed parts were decidedly 
preferred, the lime being as effective a deterrent as the strong Bor- 
deaux mixture. Even though these experiments were fairly satis- 
factory, more work should be done along these lines at the time that 
« For details in regard to the preparation of Bordeaux mixture the reader is 
referred to Farmers' Bulletin 243, entitled " Fungicides and their Use in Pre- 
venting Diseases of Fruits." 
