Indigobush twig borer
Hystricophora taleana (Grote)
From: Solomon, J.D. 1995. Guide to insect borers of North
American broadleaf trees and shrubs. Argic. Handbk. 706. Washington, DC:
U.S. Department of Agriculture, Forest Service. 735 p.
Hosts. Indigobush. Indigobush is the only known host.
Range. Collected from Washington and Sharkey Counties in
Mississippi and Chico County in southeastern Arkansas.
Description
Adult. Grayish brown moth that is somewhat bell shaped when
wings at rest (Heinrich 1929). Leading apical half of forewing with three
alternating orangish brown and metallic streaks; triangular orangish brown patch
occurs in apical third of forewing, crossed by three metallic bars with distinct
black dashed between bars. Leading basal half lighter than rest of
wing. Hindwings uniformly grayish brown. Wingspans of 13 to 17
mm. Head and thorax semilustrous and uniformly colored orangish yellow to
brown.
Larva. Plump, pale white with brown head and light brown
pinacula; about 14 mm long when mature.
Pupa. Light brown and about 12 mm long.
Biology. Adult moths have emerged from plants kept in cages
during May and June in Mississippi. Larvae develop in infested shoots and
make only short tunnels in twigs and terminals. Pupation occurs in
burrows, and the pupae move partly out of the shoots for moth emergence.
Enlarged shoots have been found after May and June emergence, indicating delayed
emergence or possibly more than one generation per year.
Injury and Damage. Infested shoots appear stunted and curl
apically. Apical portions of shoots often wither and die back.
Clumps of fine brown frass may be present either at the shoot apex or at the
juncture of a leaf petiole. Cutting open the swollen shoot reveals the
burrow and sometimes the larva. Infested parts of terminals and twigs
appear swollen and become greatly enlarged, sometimes reaching two or three
times their normal diameter. Some shoots seem to be appropriated almost
entirely for the development of larvae. Pupal skins often protrude from
enlarged shoots. Heavy infestations can cause noticeable dieback of
individual plants, but infestations are usually localized and rarely cause
serious damage.
Control. Natural controls have not been observed, and direct
controls have not been needed.
Damage in indigobush. James Solomon,
USDA Forest Service. |
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