adult - dorsal view
Distribution
Originally from South America (Argentina, Peru, Chile, Uruguay), whitefringed beetles are
now widely distributed throughout the southern United States (AL, AK, FL, GA, LA, MO,
MS, NC, SC, TN, TX, VA) and occur in New Zealand (Buchanan 1939, 1947; Warner 1975).
Description
Adult: Female (males unknown) light to dark gray or brown, with a lighter band along the
outer margins of the wing covers, and two paler longitudinal lines on each side of the thorax
and head, one above and one below the eye; length ca. 12 mm. Flightless; underwings
rudimentary, inner margins of outer wings fused together.
Egg: About 0.9 mm long X 0.6 mm wide; newly laid egg white, turning light yellow after four to five days.
Larva: Mature larva about. 12 mm long; creamy yellowish-white; C-shaped with a strong thoracic swelling.
Pupa: About 12 mm long; color creamy-white (Buchanan 1939, Young et al. 1950, Anderson
1938).
Biology
Adult beetles (univoltine = one generation per year) emerge from the soil from May to
October and feed on foliage. Oviposition (parthenogenetic reproduction) occurs five to 25
days after emergence. Egg masses (11 to 14 eggs) are laid on plant stems, roots, soil, and
where they contact the soil onto hay, firewood, lumber, and farm tools and machinery. Eggs
hatch 11 to 100+ days after oviposition (summer eggs average 17 days; winter eggs average
100 days). Larvae feed on roots, tubers, and underground stems as well as dead plant material
and complete their development in the soil. Whitefringed beetles overwinter as larvae.
Pupation occurs from late April to late July in cells constructed by the larvae; however, some
larvae spend a second year feeding on plants in the soil before they pupate. Most pupal cells
are 5 to 15 cm below the soil surface; however, cells have been found at a depth of 36 cm. In
the summer months, the pupal stage lasts ca. 13 days; in cooler months it is longer (Young et al. 1950).
Host Plants
Whitefringed beetles have been associated with over 385 plant species. The most common hosts are cotton, peanuts, okra, velvetbeans, soybeans, cowpeas, sweet potatoes, beans, and peas (Young et al. 1950, Johnson and Tappan 1987). Adults seem to prefer plants with large, broad, smooth leaves; larvae feed on agricrop plant roots, newly germinated acorns and nuts, and the roots of woody plants (e.g., peach, pecan, tung, willow) (Young et al. 1950) and pines.
Survey and Detection
The results of root feeding by whitefringed beetle larvae can range from scattered areas of a
few dead or dying plants within a field to nearly all plants being damaged. Examine roots of
affected plants: larval feeding appears as small to large amounts of decortication or partial to
complete removal of tap roots(s), below-ground portions of the stem, and some lateral roots.
Sample for larvae during the months of August through May by removing ca. 0.3 m3/soil (ca.
15 cm deep) and sifting through soil sieves 8, 16, 24, 40-mesh/2.5 cm screens).
Management
Considerable federal and state control efforts have been directed toward suppression of
whitefringed beetles. Quarantine regulations were enacted soon after discovery of the beetles,
yet the pests continued to spread. In 1940, ca. 409 acres of crops were damaged by
whitefringed beetles in Florala, and by 1944 over 4,000 acres were damaged (Brown 1951).
Chemical: Various insecticides have been employed or tested to control whitefringed beetles (e.g., DDT (Brown 1951), carbaryl (Gross and Harlan 1975), diflubenzuron (Henzell et al. 1979), cryolite (Brown 1951), dieldrin, aldrin, and chlordane (Boutwell and Watson 1978)). Many of these are no longer legal for use, even by licensed applicators. Links to current management recommendations from the University of Florida are listed here.
Insect Management Guide for field crops and pastures
Insect Management Guide for forests and shade trees
Insect Management Guide for fruit and nuts
Insect Management Guide for ornamentals
Insect Management Guide for vegetable crops
Cultural: Practices include: (1) planting oats or other small grains, which are much less
preferred by the beetles due to their fibrous root systems; (2) limiting acreage planted to
summer legumes (e.g., peanuts, soybeans) and placing leguminous crops on a three to four
year rotation. The persistence of whitefringed beetle populations in an area of land is
noteworthy and speaks for the difficulty of achieving control. In some parts of Florida, pine
plantations on converted agricrop land (particularly with soybean, peanut, cotton cropping
histories) have failed, not only on land with no fallow period between agricrop and pine, but
also up to three to four years after the last agricrop planting.
Selected References
Author: Wayne N. Dixon, Florida
Department of Agriculture and Consumer Services, Division of Plant Industry.
Originally published as DPI Entomology Circular 309. Updated for this publication.
Photographs: James L. Castner, University of Florida; and Wayne N. Dixon, Division of Plant Industry
Drawing: Wayne N. Dixon, Division of Plant Industry
Project Coordinator: Thomas R. Fasulo, University of Florida
Publication Number: EENY-294
Publication Date: June 2003
Copyright 2003 University of Florida
Featured Creatures
Department of Entomology and Nematology
Division of Plant Industry
Electronic Data Information Source
adult - lateral view
larva