18 
THE WESTERN CABBAGE FLEA-BEETLE. 
{Phyllotreta pusilla Horn.) « 
In some of the Western States not inhabited to any extent by any of 
the preceding species there is a small dark-colored flea-beetle uniformly 
deep polished olive green, with the surface irregularly punctate 
(fig. 11) which, as its English name indicates, affects more partic- 
ularly cabbage and related crops. During 1901 it was observed doing 
considerable damage to sugar beet in portions of Colorado. It prefers 
the younger plants, and as instance of its destructiveness one grower 
reported that he had not raised a turnip for seven years on account of 
its ravages. Between 10 and 20 acres of corn were reported destroyed 
on one farm in twenty-four hours, the beetles sometimes coming in 
swarms like black clouds and covering the plants. This flea-beetle 
ranges from the Dakotas to Mexico, and westward 
to southern California, being found in numbers at 
high elevations in the Rocky Mountain region. 
REMEDIES. 
The arsenicals, especially Paris green, are the 
most useful remedies for leaf -feeding beetles, and 
since Bordeaux mixture is extremely distasteful to 
flea-beetles, this, if mixed with the insecticide and 
applied as a spray, is more effective than when the 
FIG. ii.-PhyUotreta pa- arscuical is uscd dry. Against some species, how- 
siiia— much enlarged evcr, Paris green mixed with 20 parts of flour and 
of E^ntomoio'gy)^.^^^^^^ dustcd on infcstcd plants has been found satisfac- 
tory, while kerosene emulsion and even strong soap 
washes have been found useful in combatting others. When the plants 
are quite young the spray can not be so well used as after they have 
attained larger growth, but the dry mixture can then be applied with 
best results. Bordeaux mixture used alone is valuable as a deterrent. 
Clean culture is also of the greatest value. It consists in keeping 
down weeds which serve as food for the beetles and as breeding places 
for their larv8B. Against the spinach flea-beetle we have to destroy 
the chickweed and lambsquarters of the vicinity and to avoid the 
planting of beets and spinach in ground which has become overgrown 
with these plants. For the pale-striped flea-beetle, lambsquarters, 
cocklebur, and pigweed should be destroyed, while for insects like the 
smartweed flea-beetle practically all weeds in the vicinity must be pulled 
up and destroyed, as this insect feeds on nearly all forms of useless 
vegetation. The time for performing this work varies according to 
« In early publications, for example, in the Report of this Department for 1884, p. 
308, this insect was mentioned as Phyllotreta albionica owing to the fact that the two 
species had not been separated, albionica being the older name. 
