28 FARMERS’ BULLETIN 657. 
have been used to kill the bugs where they have become alarmingly 
abundant. One serious objection to these materials is that they are 
very often injurious to the plants. However, it is sometimes better 
to sacrifice the first few rows and save the cornfield than to let the 
bugs have their way. 
DESTRUCTION OF CHINCH BUGS WHILE IN HIBERNATION. 
The burning of grasses and rubbish about the farm during winter 
to destroy hibernating chinch bugs has been often recommended and 
is doubtless the most effective measure to be taken against future 
ravages of the pest. 
In the Southwest the chinch bugs are known to congregate in 
bunches of grass in late October and remain there till the warm days 
of early spring. It is only a matter of burning off these grasses at 
the proper time effectually to rid such places of the pest, and the 
grasses are generally sufficiently dry to burn readily by the first of 
of November. The chinch bugs crawl deep down among the grass 
stems, a few of them even getting beneath the dust and débris, thus 
seeking protection from the freezes that are to come. It is very 
important that the grass be dry and yet burn slowly, so that the heat 
will thoroughly penetrate the dense grass and reach the bugs. It is 
not necessary for the fire to come into direct contact with the bugs 
in order to kill them, as they died very quickly in the laboratory 
when exposed to the heat of a flame from 12 to 20 inches distant, 
the fatal temperature being in these experiments about 111° F. Fall 
burning of the grasses among which the bugs are congregated has a 
twofold value—first, it will kill large numbers of bugs directly; and, 
second, the bugs not killed by the fire will be left exposed to the 
winter freezes, which of themselves will in ordinary seasons kill 
many of them. On several occasions during fall and spring bugs 
were removed from the stubs of burned grass and the percentage of 
dead and live bugs obtained. On an average about 75 per cent were 
killed in the fall and about 63 per cent in the spring. In the spring 
about 20 per cent of the bugs which hibernated in the clumps of 
grasses were dead from exposure and other causes. From natural 
causes and burning in spring about 83 per cent of the bugs were 
dead. These percentages were obtained by actual count of the 
insects and are not from estimates. The fire can not reach all the 
bugs, even with the most careful burning, because of protection 
afforded by green or wet stems in early fall and late spring; there- 
fore it is essential that the grass be burned during late fall or early 
winter. While this remedy is recommended above all others, its 
effectiveness is entirely dependent upon the farmers and their coop- 
eration, but it is an easy matter for neighborhoods to combine in an 
effort to fight the pest in this manner. 
WASHINGTON :; GOVERNMENT PRINTING OFFICE; 1915 
