United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine
DETERMINING THE CATCH OF CIGARETTE BEETLES
IN SUCTION-LIGHT TRAPS IN CIGAR FACTORIES
OR CIGAR-TOBACCO STORAGES
By Joseph N. Tenhet and C. 0. Bare
Division of Truck Crop and Garden Insect Investigations!-
The suction-light insect trap, described by Reed et al. (1), has
been used for more than 15 years for determining the abundance of
cigarette beetles (Lasioderma serricorne (F.)) and tobacco moths
(Ephestia elutella (Hbn.)) in tobacco warehouses and factories. In
warehouses and factories handling cigarette tobacco, both these in-
sects are usually present. Methods for determining the numbers of
these insects caught in the trap have been described by Brubaker and
Pollard (2). In cigar factories and storages for cigar tobacco, how-
ever, the cigarette beetle is usually the only insect pest of economic
importance. Two simple methods may be employed for determining
the number of cigarette beetles caught in such buildings. A brief
descriptionof these-methods is given in this paper.
Before the number of the insects can be determined, they must be
killed or anesthetized. This is most readily done by suspending a ball
of absorbent cotton saturated with chloroform, carbon tetrachloride,
or ether in the covered glass jar in which the insects are caught
(fig. 1). A suitable ball, 1 to 1 1/2 inches in diameter, can be made
by winding thread or fine cord about a small piece of absorbent cotton
to make it fairly firm. A piece of cord 8 or 10 inches long should be
left fastened to the ball to facilitate handling.
Many species of insects are caught in a suction-light trap, and it
is necessary to separate the cigarette beetles from the others. This
can be easily done by use of sieves. Two sieves are usually sufficient--
one with approximately 12 or 14 meshes per inch and the other with
1/ The authors are indebted to R. W. Brubaker, H. N. Pollard,
and other workers at the Stored Tobacco Insect Laboratory, Richmond,
Figure 2. --Sieves used for separating cigarette
beetles from other insects caught in suction-
Figure 1. --Apparatus for
anesthetizing or killing
insects caught in a
Figure 3. --Graduate used
in measuring quantities
of cigarette beetles caught.
Figure 4. --Determining the number of cigarette
beetles by halving the catch.
20 meshes per inch (fig. 2). The first sieve screens out house flies,
mosquitoes, and other larger insects, but permits the cigarette beetle
to pass through. The second sieve retains the cigarette beetle but
permits passage of fine dust and trash.
The suction-light trap should be operated continuously (24 hours a
day), and the catch determined at 7-day intervals or less. When the
cigarette beetles are abundant, it may be desirable to make daily
determinations. The glass jar should be removed from the trap, a
cover screwed on immediately, and the jar replaced by a clean one.
The ball of cotton saturated with the anesthetic should be suspended
for 10 to 15 minutes in the jar containing the insects. After the cigarette
beetles have been separated out by use of the sieves, the number present
is determined. If there are fewer than 100 they may be counted manually.
If more than 100 beetles are caught, measuring them by volume in a
graduate showing cubic centimeters (fig. 3) is the most satisfactory
method, since it has been found by actual count that approximately
1, 000 cigarette beetles occupy 3 cc. The beetles should be poured into
the graduate and the graduate tapped lightly once or twice to settle them
to a uniform density. An estimate can then be made readily.
If a graduate is not available, another useful method for rapidly
estimating the number of a large quantity of beetles is by division of the
catch. The insects are placed on a sheet of paper and arranged in a
uniform conical pile. By use of a straightedge the pile is divided into
halves and one half discarded, as shown in figure 4. This process is
repeated until a pile small enough to be readily counted is obtained.
The number of beetles in this pile is multiplied by 2 for each time the
pile was halved. For example, if a pile of beetles was halved eight
times and a count of one of the final halves shows 57 beetles, then the
total catch is 57 multiplied by 2 eight times, or approximately 14, 592
Occasionally the trap catch may contain other species of approxi-
mately the same size as the cigarette beetle, which cannot be separated
from this beetle by screening. In such a contingency it is necessary to
measure the entire lot of insects, then mix them thoroughly and count a
After making the count of the cigarette beetles, it is important to
destroy them, preferably by burning. If not destroyed, some of them
may recover and reinfest the factory or storage warehouse.
UNIVERSITY OF FLORIDA
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(1) Reed, W. D., Morrill, A. W., Jr., and Livingston, E. M.
1935. Trapping experiments for the control of the cigarette
beetle. U.S. Dept. Agr. Cir. 356, 13 pp., illus.
(2) Brubaker, R. W., and Pollard, H. N.
1941. Determining the catches of cigarette beetles and tobacco
moths made in insect traps. U. S. Bur. Ent. and Plant
Quar. Cir. ET-186, 4 pp., illus. O'rocessed2