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Asian Ambrosia Beetles |
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Xylosandrus crassiusculus (Motschulsky) |
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Dr. H C Ellis,
Professor and Extension Entomologist, The University of Georgia, Department of Entomology, Tifton, GA 31793 Dr. D. L. Horton,
Professor and Extension Entomologist, The University of Georgia, Department of Entomology, Athens, GA 30602 |
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In: Roberts, P. M. and G. K. Douce, Coordinators. 1999. Weevils and Borers. A County Agent's Guide to Insects Important to Agriculture in
Georgia. Univ. of GA, Col. Ag. Env. Sci., Coop. Ext. Serv., Tifton, GA USA. Winter School Top Fifty Agricultural Insect Pests and Their Damage Sessions, Rock Eagle 4-H Ctr., Jan. 20, 1999. |
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Order Coleoptera: Family ScolytidaeDescription: Adult females are minute (2 to 3 mm), stout bodied, dark reddish brown, and have a hunched-back appearance. Males are smaller, about 1.5 mm long. The head of adults
is completely hidden when viewed from above. Larvae are white, legless, C-shaped, and indistinguishable from other scolytids.Hosts: Entered the United States at Charleston, South Carolina about
1974. Now known to attack various trees and shrubs, including pecan, peach, plum, cherry, persimmon, oak, elm, sweet gum, magnolia, fig, buckeye, and sweet potato. It probably will attack other plants on
which it has yet to be found. Damage: Adults and larvae bore into twigs, branches or small trunks of woody host plants, excavate a system of tunnels in the wood or pith and introduce a symbiotic
ambrosial fungus on which they feed. The boring and introduced fungus damage and clog the xylem, ultimately killing all or part of the plant. Infestations normally can be identified by toothpick-like spines
of boring dust protruding from holes made in the host plant by females excavating their galleries. The strings or spines of boring dust may be up to 2 to 3 inches long but are fragile and easily broken off by wind
or rain. Unlike other scolytids, which normally attack only stressed or damaged plants, Asian ambrosia beetles attack apparently healthy plants. Individual plants may host up to 50 beetles. It is
almost impossible to save heavily infested plants. Life Cycle: They are active year-round during warm periods but most adult activity has been observed in March. They mate, lay eggs and rear young within
the galleries excavated by the females. They breed in host material from 2 to 30 cm in diameter, although smaller branches are most commonly attacked first. All life stages can be found inside the galleries.
When mature, females leave infested plants and fly to new host plants. Males do not fly. There are several generations per year. Control: Infested plants or plant parts should be removed and
burned. Insecticide applications to the trunks of surrounding plants may help reduce infestations. Up to four applications of a residual chemical, repeated ever six to eight weeks, may be necessary to stop
an infestation. |
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Updated from: Horton, D. L. and H C Ellis, 1997. Weevils and Borers. In: Hudson, R. D. and D. B. Adams. 1997. A County
Agent's Guide to Insects Important to Agriculture in Georgia. Entomology 97, RDH (1). Univ. of GA, Col. Ag. Env. Sci, Coop. Ext. Serv., Tifton, GA 31793. |
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