324 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 17 
CONTROLLING CHINCH BUGS IN MISSOURI WITH CALCIUM 
CYANIDE 
By Leonard Haseman and S. W. Bromley 
Abstract 
The results secured from the use of the new chemical calcium cyanide for destroy¬ 
ing chinch bugs at wheat harvest are given. Calcium cyanide did not prove practical 
when sown broadcast in infested wheat fields or when applied as a line barrier on 
the surface of the ground. In tests where it was applied in a narrow strip or trap 
crop between wheat and corn fields, it proved promising. However, best results 
were secured when the material was distributed in a narrow line in the bottom of a 
deep narrow furrow such as made with a plow. The furrow should have practically 
a vertical wall next to the crop to be protected and a line of the chemical placed 
at the foot of the vertical wall. One pound of calcium cyanide flakes to each sixty- 
linear feet of furrow applied in the afternoon when heavy migration of bugs began, 
proved effective in destroying the bugs for the rest of the day. This requires about 
22 pounds, costing four dollars a day for material used in a quarter of a mile of 
barrier. 
The chinch bug is one of the few serious naturalized insect pests of field 
crops. A glance at the literature dealing with the chinch bug shows 
it to have been one of our earliest and most important insect scourges. 
The early writings of Riley, Walsh, Webster, Forbes and others abound 
with descriptions of chinch bug epidemics, the life history of the pest 
and methods of controlling it. In fact, a careful study of these early 
writings and most of the later articles on this insect leads one to wonder 
if the earlier workers actually left much for the present day entomologists 
to find out either as regards life cycle or control. 
Who first observed the wintering habits of the pest and recommended 
winter burning of grass and other rubbish to destroy the hibernating 
adults? What important new discoveries or recommendations have 
we made recently on this phase of the subject? Likewise who 
first found that at wheat harvest, the pest by migrating to corn again 
exposed itself to flank attacks with barriers? Who first recommended 
the use of dust barriers, and who the chemical barriers? What new 
discoveries have we made along the line of barriers in the last 
thirty years? Some new chemicals have been developed and some 
improvements made along the line of methods, but when all is said 
and done we of the younger generation must frankly confess that we 
have closely followed the worn entomological paths. The senior 
author can say this frankly and without fear of offending any co-worker 
in the chinch bug field, where he himself has labored these many years. 
These general remarks are meant neither as fault-finding nor as an 
apology, but rather as a challenge to the younger men. That the 
