Mimosa Webworm
Contact: Eric Day, Manager, Insect Identification Laboratory
August 1996
Mimosa Webworm
Lepidoptera: Glyphipterygidae, Homadaula anisocentra
Plants Attacked
Honey locust and Mimosa
Description of Damage
Larvae feed on the leaf surfaces. The foliage is usually skeletonized.
The lower epidermis is usually
entirely destroyed. Leaves die and turn dull gray on mimosa;
brown, as if fire-scorched on honey locust. Leaves and flowers
are webbed together as larvae feed and develop. Usually the
entire tree is involved with larvae scattered here and there
throughout the foliage. Leaflets from different leaves often
are webbed together. Repeated attacks seriously weaken trees,
occasionally leading to death of some trees.
Identification
Larvae are grayish to dark brown, sometimes
tinged with rose or pink and are 1/2" - 1" long. Five white
stripes run the length of the body. The larvae are extremely
active, wriggle violently, and drop on silk strands when
disturbed much like many leaf-rollers. The adult moth may seldom
be seen, but has about 1/2" wing span. Wings are gray with
silver sheen and black dots.
Life History
Moths appear in June and lay eggs on mimosa
flowers and foliage. The larvae feed gregariously within a web
spun over flowers and leaves. In midsummer larvae descend to the
ground on silken threads and spin cocoons in cracks in bark or in
ground cover. The webbing is most conspicuous in August from the
2nd brood. Second generation pupae overwinter in crevices on
tree trunks or protected by soil cover or litter. There is
considerable overlap of generations.
Control
Since many eggs are laid initially and the young larvae
begin to feed extensively, trees should be watched for the
earliest signs of feeding, in June. Larvae are more difficult to
control when larger and webbing is extensive. Adult moths are
active over a period of time, so new eggs may be laid after
effects of earlier sprays have dissipated.
Remarks
Sunburst honeylocust is reported to be most susceptible
with Moraine, Skyline, and Shademaster less so, although damaged
severely. It is helpful to keep leaf and other debris raked up
under host trees. Honey locust is more if not as susceptible as
mimosa.