LIFE HISTORY AND CONTROL OF HOP FLEA-BEETLE. 
55 
reach them. Painting the poles with crude oil or a thick crude-oil 
paint with the idea of blocking the beetles in was another suggestion, 
and several experiments were conducted along this line. Whiting 
was used as a filler and the poles were thoroughly coated with the 
mixture. This formed a sticky coating when first applied, but the 
oil was soon absorbed by the wood, and neither acted as a barricade 
nor a sticky trap for those that might crawl up the pole. At the 
time that the majority of the beetles were believed to be hibernating 
in the trellis poles, clipping them in hot crude oil was offered as a 
sure cure. This process, if properly handled, would probably de- 
stroy all the beetles that were in the poles, but the few present in that 
situation did not war- 
rant such expense. A 
fumigatorium (fig. 16) 
was made which could 
be placed around a 
trellis pole, and many 
fumigation experi- 
ments were tried dur- 
ing the winter. When 
the thermometer was 
below 32° F. the bee- 
tles were apparently 
unaffected by the 
gases, and under field 
conditions the wind 
blew so hard that it 
was impossible to 
make the fumigator- 
ium tight enough for 
effective work. Such 
a method, too, would 
require a great deal of 
time and labor, and as a practical control measure is out of the 
question. Several attempts were made to burn the beetles that were 
in the poles. In one experiment kerosene was painted on the wood 
and lighted, and in another an oiled gunny sack was lighted and 
wound around the base of a pole which was then inclosed in the 
fumigatorium. By the latter method a few beetles were killed, but 
as wood is such a poor conductor of heat few were heated sufficiently 
to injure them. 
Rolling the yards. — The fact that beetles were observed hibernating 
in the grass and just under the surface of the soil led to the sug- 
gestion that rolling the yards with a heavy roller would kill a large 
66513°— Bull. 82—12 5 
Fig. 16. — Fumigating trellis poles to destroy hop flea- 
beetles. (Original.) 
