INSECT NOTE # P-3
An insect pest of fruit, nut and woody ornamental trees is causing significant damage. throughout North Carolina.
IMAGES:DAMAGE: Female beetles bore into stems and young trees. Visible symptoms include wilted foliage and strings of boring dust from small holes. Serious attacks may result in tree death. Galleries may be observed internally. A symbiotic ambrosial fungus is associated with this insect.
DISTRIBUTION: The Asian ambrosia beetle was first detected in the U.S. in peach trees in Charleston, South Carolina in 1974. Since then it has spread to Alabama, Florida (1983), Georgia, Louisiana, Maryland (1993), Mississippi (1980), North Carolina (1979), Oklahoma (1994), Tennessee (1993), Texas (1984), Virginia (1995) and Oregon (1995). It has been reported from 18 North Carolina counties.
KNOWN HOSTS: Pecan, peach, plum, cherry, persimmon, golden rain tree, sweet gum, Shumard oak, Chinese elm, magnolia, fig, Mexican buckeye and sweetpotato are susceptible to attack.
DESCRIPTION: Infestations can be identified by toothpick-like strands protruding up to 1.5 inches from the host plant. The spines are strings of boring dust produced by the female beetle as she excavates her gallery. The strands are fragile and are easily broken off by wind or rain. Individual plants may host from one to more than 50 individual beetles. Although adults are present most of the year, clinic records indicate they are most active during March.
LIFE HISTORY: Females bore into twigs, branches, or small trunks of susceptible hosts. They excavate tunnels in the wood, introduce a fungus and produce a brood. Eggs, larvae and pupae are found together. There are no individual egg niches, larval tunnels or pupal chambers. Attacks may occur on apparently healthy, stressed, or freshly cut hosts. High humidity is required for successful reproduction. Females remain with their brood until maturity. Males are rare, small and flightless. Females mate with their brothers if present before emerging to attack a new host.
CONTROL: Infested plants or plant parts should be removed and destroyed. Trunks of trees should be treated with an insecticide. Endosulfan (Thiodan, Phaser) or chlorpyrifos (Lorsban) are effective against related Scolytid beetles and may give some control if applied in a timely manner and with thorough coverage. Be sure and check label for specific information and limitations. Keep trees healthy and avoid any unnecessary tree stress (drought, injury, nutrition, etc.). Some traps may be used to monitor for adult beetles. Check trees frequently in March and treat accordingly.
Prepared by:
K. A. Sorensen, Extension Entomologist,
North Carolina State University
Sept 1995
mtw
