Whitefringed Beetles, Graphognathus leucoloma (Boheman), G. minor (Buchanan), G. peregrinus (Buchanan) and G. fecundus Buchanan

Leininger, T.D; Solomon, J.D.; Wilson, A. Dan; Schiff, N.M. 1999. A Guide to Major Insects, Diseases, Air Pollution Injury, and Chemical Injury of Sycamore. Gen. Tech. Rep. SRS-28. Asheville, NC: USDA Forest Service, Southern Research Station. 44 p.

Importance.-Whitefringed beetles were introduced into Florida in 1936 and have spread north to Virginia and west to Louisiana. They feed on over 300 plant species. On young sycamore trees, the larvae destroy both tap and lateral roots. Damage may occur in new nurseries and first-year plantations established on sites with heavier soils not well suited for sycamore production.

Identifying the Insects (fig. 20a, b).-Adults are dark-gray, 9-mm-long beetles with a white fringe along the outer margins. Full-grown larvae are yellowish white, C-shaped, legless, and 12 mm long with a pale head. Eggs are oval and pale yellow.

Figure 20a. - Whitefringed beetle Photo by Gerald J. Lenhard

Identifying the Injury. (fig. 2Oc).-Damaged plants become chlorotic and may die; injured survivors appear yellow and unhealthy. Excavation will reveal root injury. Larvae can be found in the top 12 to 24 cm of soil. Adults may be seen resting around the bases of plants.

Biology.-Overwintering larvae begin pupating in April, and adults emerge from May to October. All adults are females, each of which deposits up to 1,500 eggs in the soil in masses of 11 to 14. Eggs hatch in 11 to 30 days, and larvae feed on plant roots. There is one generation per year. Adults cannot fly, but the insect is easily spread by moving infested plants, soil, or equipment.
Figure 20b. - Larvae	Figure 20c. - Larval feeding injury to roots of sycamore seedling. Photo by James Solomon, USDA Forest Service

Control.-Commercial traps are available to monitor infestations. Fallowing heavily infested soils will reduce populations.