48 SOME INSECTS INJURIOUS TO TRUCK CROPS. 
BACTERIAL DISEASES. 
Beetles which were brought into the laboratory between the 10th 
and 14th of June died off in large numbers. They had a very sour 
odor about them which was not noticed around beetles which died 
earlier in the spring. This great mortality, accompanied by the sour 
odor, indicates the possible existence of a bacterial disease. An 
endeavor was made to determine this point, but the beetles in the 
check cages died as rapidly as those which were exposed to infection, 
and no conclusion could be drawn. 
PARASITES AND PREDACEOUS ENEMIES. 
Xo parasites attacked the beetles during the spring generation, 
and none has so far been observed on beetles in British Columbia. 
Although the adults have no known predatory enemies, with the 
possible exception of some birds, the younger stages, especially the 
larva?, are subject to the attack of several creatures. The larva of 
one of the Carabida? was quite plentiful in the soil, and under 
laboratory conditions was observed to feed voraciously upon the flea- 
beetle larva?. Two species of centipedes were also numerous, but only 
one was observed feeding upon the larva?. This species was very 
common in the hopyards and probably destroyed a large number of 
beetle larva?. 
CONTROL MEASURES. 
The fact that the beetles hibernate in the soil as well as in the poles, 
vine-stubs, and string-pegs, that the younger stages are all passed 
beneath the surface of the soil, and that, when they emerge, the adults 
are not readily killed by arsenicals or by contact insecticides, made 
the control problem at first appear to be a difficult one. During the 
spring and summer even 7 feasible method of control was carefully 
tested, and of the following measures the application of tanglefoot 
and. under some conditions, the use of the sticky shield have proved 
to be the key to the flea-beetle problem. 
THE TARRED BOARD OR STICKY SHIELD. 
The hibernating beetles, unless in unusually large numbers, will 
not require any attention, but the sudden appearance of the first 
generation just before the vines are trained may require the use of the 
tarred board or sticky shield. 
The tarred board which was used during the spring of 1909 was 
made by stretching a piece of 8-ounce canvas over a light wooden 
frame. 4 feet long b} T 3 feet wide. A 4-foot strip attached to the 
