Persimmon agrilus
Agrilus fuscipennis Gory
From: 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.
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.
Damage. James Solomon,
USDA Forest Service. |
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