Persimmon Agrilus
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Hosts
Persimmon. Persimmon is the only confirmed larval host, but adults have been collected on sourwood (Chamberlin 1926, Fisher 1928).
Range
A southeastern species, recorded mostly from North Carolina west to Texas but reportedly occurring as far north as Ohio (Chamberlin 1926, Fisher 1928)
Description
Adult
Large, elongate, robust, and slightly flattened beetle, 12 to 14 mm long and 3.3 to 4 mm wide (Fisher 1928). Head and pronotum dark copper with strong reddish purple tinge and black elytra. Beetles more shiny below than above, and bronzy black with anterior parts blending to blackish olive. Pronotum three-fourths wider than long and widest at middle. Sides of abdomen narrowly exposed and visible from above.
Larva
Long, very slender, and white except for dark brown mouthparts and anal forceps. Prothorax slightly wider and mesothorax and metathorax slightly narrower than abdominal segments.
Biology
Adults begin emerging in spring and have been collected from March to July (Fisher 1928). Females apparently oviposit on the lower trunk. Larvae burrow into the wood and make long galleries in both the lower trunk and roots. Dissections reveal that galleries are most prevalent around the root collar and commonly occur 1.2 m up into trunks and 0.5 , down into roots. However, a few galleries have been found in trunks to 2 m and in roots to 1 m. Pupation occurs in chamber in the lower trunk. The life cycle is little known, but based on gallery lengths and sizes, it is likely that development takes more than 1 year.
Injury and Damage
Infestations are difficult to detect in living trees. Although removing bark sometimes reveals burrows, cutting into the trunk and excavated roots is usually required to expose galleries. Long, narrow galleries within wood in the lower trunk and roots extend longitudinally and generally straight courses with only slight bends. Galleries are flattened ovals in cross section and measure 1.0 to 3.5 mm by 0.5 to 1.0 mm. Galleries are tightly packed with fine frass that is slightly lighter to slightly darker than surrounding wood. A thin layer of wood (0.5 to 2.0 mm) immediately surrounding the galleries in both trunk and roots is typically stained black. Up to 15 galleries per tree have been observed in cross sections from the lower trunk. This borer apparently causes little or no mortality. However, its tunnels in the wood are considered defects that interfere with the manufacture of specialty wood products and result in degraded logs of less value.
Control
Nothing is known of natural controls, and direct controls have not been needed.
References
Solomon, J.D. 1995. Guide to insect borers of North American broadleaf trees and shrubs. Agric. Handbk. 706. Washington, DC: U.S. Department of Agricultural, Forest Service. 735 p.
