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THE BEET LEAF-BEETLE. OF: 
alone. The benefits derived from the repellent effect were, however, 
usually of little importance. 
Paris green, whenever eaten by the beetles, proved somewhat 
quicker in its killing effect than either arsenate of lead or zinc arsen- 
ite. Paris green, 1 pound to 50 gallons of water, gave more promis- 
ing results than any other mixture. When applied thoroughly to 
the upper and lower surfaces of the leaves a fairly good number of 
beetles were killed but when apphed to the upper surface the re- 
sults were entirely unsatisfactory. In one experiment at the fore- 
going strength a large number of beetles, which had recently emerged 
from their cells and were too soft to fly, crawled to the sprayed beets 
and were promptly killed. Such instances as this, however, are 
exceptional. As a rule the newly-developed beetles feed upon weeds 
until they become hardened and then fly. to the beets. When they 
are able to fly the majority almost invariably desert or avoid sprayed 
or dusted plants. Even in exceptional cases when the beetles are 
killed, others usually take their places promptly, and unless frequent 
applications of the poison are made the results are of little benefit. 
In one xperiment 20 acres of beets were sprayed twice and in an- 
other 5 acres were sprayed three times, but the results were only tem- 
porary and did not justify the expense. 
In dusting experiments the majority of the beetles refused to eat 
the treated foliage and few were killed. The “dust” served as a 
repellent for a few days but this protection was too brief to be of 
practical benefit. 
The larve are readily killed with Paris green but they seldom 
occur in sufficient number on sugar beets to make it profitable to 
spray for them alone. The weeds, upon which the bulk of the 
larvee normally develop, are usually scattered about. in inaccessible 
places and it is somewhat doubtful if they could be profitably 
sprayed, except in cases of severe outbreaks of this insect. 
RECOMMENDATIONS FOR CONTROL. 
Basing an opinion on the experiments and observations which 
were conducted in the Arkansas Valley of Colorado during four 
seasons, it may be concluded that arsenicals can not be entirely de- 
pended upon as a practical means of controlling the beet leaf-beetle. 
As previously mentioned, the majority of the beetles congregate, 
during the fall, on or about alkali areas. Here they Phe on 
the surface of ie ground, under tufts of grass, heaps of weeds, or 
other shelter. The most effective and practical method of control 
is, therefore, to destroy the beetles in their hibernating quarters. 
This may be accomplished easily and cheaply between the middle 
of November and the first of March, by burning the dead grass and 
weeds. 
