MEMORANDUM REGARDING A WEEVIL NATIVE TO JAPAN
NOW KNOWN TO OCCUR IN THE UNITED STATES
By C. A. Weigel, Division of Truck Crop and Garden Insect
Investigations, Bureau of Entomology and Plant Quarantine,
United States Department of Agriculture
During 1935 the attention of this Bureau was directed to the fact that a
weevil, Calomycterus setarius Roclofs, known to be indigenous to Japan, was
spreading in the United States and becoming of increasing importance in some
of the localities where its presence has been detected. In order that in-
formation regarding the distribution, occurrence, and habits of this insect
may be available, the literature has been reviewed and other facts have been
summarized. The accompanying statement has been prepared by C. A. Weigel, with
tho assistance 'of information assembled by other offices of the Bureau, including
the Insect Pest Survey, the Library, and the Division of Insect Identification.
History and Distribution Outside of the United States
This weevil was first described from Japan in 1873 by W. Roelofs (1),*
who erected the genus Calomycterus to receive the new species C. setarius.**
The weevil is approximately one-sixth of an inch in length and uniformly pearl
gray in color. It belongs to the wingless (apterous) group of the Otiorhyn-
chidae. Consequently it is likely that its rate of natural spread is much slower
and more limited than is that of the winged forms of insects.
In addition to the publication containing the first description of the
weevil, there are only four other foreign references involving this species,
Numbers in parentheses denote references cited.
L.. ** The literature records only one other species in this genus,-
Calomycterus variabilis Kono,--and the only available references on this
species are the following:
1930. Kono, H. Kurzr*'ssler aus dem japanischen Reich. (See reference
no. 5. Original description (p. 224) and drawing. Japanese
name "Usuiro-menagazo", probably a vernacular name.)
1931. Matsumura, S. Illustrated Insects of Japan-Empire. (Text in
Japanese. Figure of adult on p. 279.)
1931. Miwa, Y. A Systematic Catalogue of Formosan Coleoptera. Dept.
Agr., Govt. Research Inst., Formosa. 359 pp. (P. 251.)
Judging from these references, all of which are systematic in character,
it appears that C_. variabilis is known to occur only in Formosa. No references
regarding its biology and economic -importance appear to be available.
namely by Lewis (2), Schbnfeldt (3), Sharp (4), and Kono (5), all of which are
systematic in character and do not contain any information regarding the
biology or economic phases of the insect. The first two authors mention merely
that the insect is present in Japan. Sharp records that it is a remarkable
and apparently rare species for which he was not able to record any exact
locality. Kono, however, lists the following localities where the insect had
been found in Japan: Honshu (Yokohama, Tokio, Sanjodake, and Gifu); Kiushu
(Kumamoto). This same author mentions that this species was known by the
Japanese name of "Chibi-menagazo", indicating that it may be sufficiently
abundant in that country to be given a common name.
History and Distribution in the United States
This weevil was first found in the United States during the summer of
1929 at Yonkers, N. Y., by E. G. Peters. Mr. Peters referred them to his
neighbor, W. M. Faunce, of the American Museum of Natural History, at New York
City. Mr. Faunce referred these specimens to A. J. Mutchler, of the American
Museum of Natural History, who published a note (6) on this occurrence in
March, 1930. According to the original account, the weevil adults were causing
considerable damage to American and Japanese ivy and were feeding to a lesser
extent on rose bushes, geraniums, and woodbine. Later these weevils became so
numerous that many thousands of them were attracted to the light-colored paint
on the nearby residence of Mr. Faunce, and to any light-colored object located
in the vicinity. It is recorded that these weevils were so numerous that
trouble was experienced in excluding them from the residence of Mr. Faunce,
even with the windows and doors screened. (Specimens determined by L. L.
W. E. Britton (7) received specimens of the weevil from Lakeville,
Conn., on January 8, 1932, with a report that the adults were numerous in a
residence. This occurrence was investigated on July 28 by M. P. Zappe, assis-
tant to Dr. Britton, who reported that he found the weevils feeding in moderate
numbers on iris, which were growing in a hot, sunny location, in close proximity
to the residence in which the specimens had been collected. The iris plants
which were shaded by a privet hedge located close to the residence were injured
to a greater extent than iris growing at a more remote distance from the resi-
dence. The weevils were very numerous on the hatchway leading to the cellar,
located at the southwest corner of the residence. Vegetable plants growing
nearby had not been injured by the weevil, but an occasional beetle was found
on Swiss chard. The food plants referred to by Dr. Britton in this report con-
sist of iris, bindweed (Convolvulus sp,), phlox, and smartweed (Polygonum sp.).
(No statement regarding the specific determination of this weevil.)
On July 23, 1935, Britton (8) reported that C. setarius was injuring
chrysanthemums and other plants in a greenhouse at Sharon, Conn., located ap-
proximately 4 or 5 miles from Lakeville, Conn., the source of the preceding
report. (Specimens determined by B. H. Walden of the Connecticut Agricultural
T. L. Guyton and A. B. Champlain (9), in June, 1935, reported C. setarius
as having been found damaging sweetpotato and yarrow at Mechanicsburg, Pa.
They found the beetles to be abundant on yarrow, generally scattered on the
flower, and quite plentiful on the sweetpotato plants. (Specimens determined
by L. L. Buchanan.)
During July, 1935, E. N. Cory (10) (and H. S. McConnell), of the Mary-
land Agricultural Experiment Station, reported the presence of the weevil in
Maryland on the estate of H. S. Jones, at Towson, Md. The owner stated that
this same insect was present on his property in 1934. Literally thousands of
beetles invaded two residences in this locality after having fed on a wide
variety of plants growing nearby. These food plants consisted of roses, milk-
weed, red clover, hollyhock, daylily (Hemerocallis), redtop, ivy, Cotoneaster
(P.vracantha), and marigold.
Food Plants and Distribution in the United States
Bindweed (Convolvulus sp.)
Smartweed (Polygonum sp.)
New York, Maryland
Guyton and Champlain
Guyton and Champlain
Summary and Conclusion
From the foregoing it is evident that there is very little known concern-
ing the life history, habits, and control of this weevil. The few references
available indicate that Japan is the only foreign country in which it occurs.
Although it has been given a Japanese name which might indicate that it is a
well-known insect in Japan, the records now available do not reveal that it is
a serious pest in that country.
Since its first recorded occurrence in New York in 1929 it has spread
to Connecticut, Maryland, and Pennsylvania.
The list of food plants includes 13 ornamental and flowering plants,
1 legume. 1 grass, 1 vegetable, and 4 weeds. The present records indicate
that it is apparently capable of doing considerable damage to some of the
plants that it attacks, viz: American ivy, woodbine, iris, phlox, sweetpotato,
yarrow, and greenhouse-grown chrysanthemum. Since some of these are commercial
crops, the weevil may become a pest of some concern, especially if it becomes
established in some of the important truck-growing regions and nurseries in this
UNIVERSITY OF FLORIDA
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Its habit of swarming around and into dwellings and constituting a
nuisance by its presence may also cause it to become obnoxious from that view-
point, in addition to its possible status as a plant pest.
Although nothing is known concerning its control, advantage may perhaps
be taken of its habit of being attracted to light-colored objects in developing
traps to catch the adults.
(1) 1873. Roelofs, W. Curculionides recueillis au Japan par M. G. Lewis. Ann.
Soc. Ent. Belg. 16: 154-192. (Calomycterus setarius, p. 175
and pl. III, fig. 9.)
(2) 1879. Lewis, G. A catalogue of Coleoptera from the Japanese Archipelago,
p. 21. London. (Systematic paper; not seen.)
Sch6nfeldt, H. v. Catalog der Coleopteren von Japan. Jahrb.
Nassauischen Ver. f. Naturkunde 40: 29-204. (C. setarius from
Japan listed on p. 143.)
(4) 1896. Sharp, D. The Rhynchophorous Coleoptera of Japan. Part IV. Otio-
rhynchidae and Sitonides, and a genus of doubtful position from
the Kurile Islands. Trans. Ent. Soc. Lond. 1896: 81-115.
(C. setarius on p. 84.)
(5) 1930. Kono, H. Kurzr'ssler aus dem japanischen Reich. Jour. Faculty
Agr., Hokkaido Imp. Univ., Sapporo, Japan, vol. XXIV. pt. 5,
pp. 152-242. (C. setarius on p. 224.)
(6) 1930. Mutchler, A. J. A Japanese weevil, Calomycterus setarius Roelofs,
which may become a pest in the United States. Amer. Mus. Novitates
No. 418, 3 pp. (Adult figured; first record in this country.)
Britton, W. E. Another Japanese weevil pest C. setarius Roelofs.
Conn. Agr. Expt. Sta. Bul. 349, p. 448. (This is also the 32nd
Report of the State Entomologist.)
Britton, W. E. In Insect Pest Survey Bulletin, Bur. Ent. and Plant
Quar., U.S. Dept. Agr., vol. 15, no. 6, p. 315. (Mimeographed.)
Guyton, T. L., and Champlain, A. B.
letin, vol. 15, no. 5, p. 251.
In Insect Pest Survey Bul-
Cory, E. N. In Insect Pest Survey Bulletin, vol. 15, no. 6, p. 315.