STATE PLANT BOA T'O
E-503 June 1940
United States Department of Agriculture
Bureau of Entomology and Plant Quarantine
METHODS USED TO COMBAT THE WHITE-FRINGED BEETLES
Prepared in Division of Domestic Plant Quarantines
Two species of white-fringed beetles (Pantomorus leucoloma Boh.
and P. peregrinus Buch.) have in recent years caused considerable damage to
crops in some localities of southern Alabama, northwestern Florida, south-
eastern Louisiana, and southern Mississippi. At the close of the calendar
year 1939 the known infested area totaled approximately 71,000 acres in the
.4 affected States. The 2 species are similar in appearance and habits.
They are destructive in both larval and adult stages to a wide range of
crops, the most serious injury being caused by the feeding of the larvae on
plant roots. Among the crops most severely damaged are corn, cotton, pota-
toes, peanuts, and other legumes. In the absence of favored host plants,
however, the insects feed on, and cause economic damage to, practically all
types of succulent vegetation.
Both species of white-fringed beetles pass the winter chiefly as
larvae in the soil, The larvae are white, grublike, and about half an inch
long when full-grown. Most of them become mature in May or June. They
pupate in cells in the soil, and the adults begin to emerge late in May or
early in June, the main emergence being between mid-June and late in July.
The robust, dark-gray adult beetles are about seven-sixteenths of an inch
long, have a thick snout, are unable to fly, and are all females. Individ-
uals have been known to live for almost 6 months, although most of them pro-
bably survive a much shorter time under- natural conditions. They lay their
eggs in small masses which are difficult to find, usually at or Just below
the surface of the soil in contact with bits of old plant stem, sticks, or
pebbles. A single beetle ordinarily lays 600 or 700 eggs, although individ-
uals have been known to lay over 3,000. In warm weather, with plenty of
moisture, the eggs hatch in about 2 weeks, and the little larvae immediately
enter the soil, where they remain, feeding more or less actively on plant
roots, until they complete their growth. There is normally one generation
Since 1937 the Bureau of Entomology and Plp.nt Quarantine of the
United States Department of Agriculture, in cooperation with the affected
States, has been conducting research and suppressive activities against these
insects throughout the infested areas, and Federal and State quarantines are
enforced to prevent their spread.
UNIVERSITY OF FLORIDA
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The types of control measures used are based on information obtained
from field observations of the life history and habits of the pests and
other studies, which show that white-fringed beetles cannot fly, that they
require green food in order, to survive and lay eggs in any numbers, that
their egg-laying capacity is greatly reduced by the elimination of favored
host plants, and that they are easily killed by the heat when exposed on
bare ground to the direct rays of the sun, as well as by insecticides, such
as calcium arsenate and cryolite, when applied to their food plants. Based
on such information, the following suppressive measures are used:
(1) Clean cultivation of infested fields to eliminate all vegeta-
tion during the period of adult activity.
(2) Use of an oil-base sodium-Rrsenite herbicide to eliminate host
vegetation on waste and abandoned areas, on railroad yards, and in the vicin-
ity of processing plants and other places from which there is danger of
artificial spread of the pests unless they are suppressed.
(3) Use of insecticides, such Ps calcium arsenate and cryolite, to
destroy the adult beetles.
(4) Use of soil fumigants to destroy the larvae.
(5) Modification of farm practices, in cooperation with farmers, to
allow more effective use of insecticides by eliminating, insofar as practi-
cable, the planting of certain leguminous crops, especially the interplant-
ing of such crops with corn.
One or more of these suppressive measures, or a combination of them,
are applied on all known infested acreage. As a result of such control
there has been a drastic reduction in population of the pest throughout all
the infested areas, and the beetles have apparently been eradicated from
several of the more isolated areas.
Further information relative to the progress of suppressive activ-
ities may be obtained from the Bureau of Entomology and PlAnt Quarantine,
U. S. Department of Agriculture, Washington, D. 0., or from the Bureau's
field station at Gulfport, Miss. (P. 0. Box 989).