August, ’23] 
FULTON: POISONING EUROPEAN EARWIGS 
369 
SOME EXPERIMENTS ON POISON BAITS FOR THE 
EUROPEAN EARWIG 
By B. B. Fulton, Oregon Agricultural Experiment Station 
Abstract 
As a stomach poison for the European Earwig, sodium fluoride has an equal or 
greater amount of toxicity than arsenious oxide and acts more rapidly. 
Wheat bran sweetened with molasses is sufficiently attractive to the earwigs for 
all practical purposes. 
The addition of amyl acetate does not increase the attractiveness of the sweetened 
bran for earwigs. 
Oat hulls are slightly more attractive than wheat bran. The adhesive property of 
the former makes it especially desirable for a bait to be applied to objects for poison¬ 
ing half grown or adult earwigs, but not so good for scattering over the ground for 
young earwigs. 
Glycerin does not lessen the attractiveness of a bait and increases the length of time 
during which the bait is effective. 
The European Earwig (Forficula auricularia Linne) which has be¬ 
come an established pest in Rhode Island and in several cities of the 
Pacific northwest, has been found to be susceptible to poison bait con¬ 
trol methods. Stale bread crumbs have been recommended for this 
purpose 1 but this material is difficult to prepare and scatter and is un¬ 
desirable for large scale operations. Preliminary experiments showed 
that wheat bran was readily taken by earwigs when attractive ma¬ 
terials are added, and since this is one of the best mediums from a 
practical standpoint, being easily mixed and scattered, it was adopted 
as a base for further experiments conducted in Portland, Oregon, 
during the summers of 1921 and 1922. 
Tests of various poison bran mixtures made during the first season’s 
work showed that earwigs are very resistant to arsenical poisons. 
Arsenious oxide or white arsenic in proportions two or three times as 
great as commonly used for grass hopper control required from two 
and a half to five days to cause death. Other tests were made using 
sodium fluoride as the poison and in every case death resulted much more 
rapidly than where an equal amount of arsenious oxide was used. 
In all of these preliminary experiments a large element of error existed 
due to the fact that the insects used in the tests were collected from open 
piles of the poison bait and there was no way of telling how long they 
had been feeding. For this reason only very general conclusions 
could be drawn from the data. 
For the experiments during the following season a small trap cage 
was devised which acted on the principle of a fly trap. The bait to be 
tested was placed in a small tight box with a screen front bent inwardly 
in the form of a wedge and having small holes at the innermost point of 
J D. W. Jones. U. S Dept. Agriculture, Bulletin 566. 
