|
PINE WEBWORM
Frass
nest of the PINE WEBWORM |
Other: |
Webworm |
| Species |
Tetralopha
robustella |
| Common Hosts: |
Japanese
black pine Pinus thunbergiana
Loblolly pine Pinus taeda
Longleaf
pine Pinus palustris
Sand pine Pinus clausa
Shortleaf pine Pinus echinata
Slash pine Pinus elliottii
Virginia pine Pinus virginiana |
Description |
Adult -- brownish-gray head and body; front wings dark at base
and tips, hind wings light brown; wingspan approximately 25
mm
Pupa -- size of adult; reddish-brown.
Larva -- size variable, approximately 20 mm long when mature;
dark and light brown head, light brown body with 4 darker strips. |
Importance |
Young (1-2 year) pine seedlings are most susceptible to webworm
infestation; older trees infrequently infested. Growth loss
may occur, but death is uncommon. Generally, few infested seedlings
are present the year following a high webworm infestation rate. |
Biology
and Habits |
Adults
moths emerge from the soil early-late spring, mate, and the
female lay eggs on the pine needles. The young larvae mine the
needles; older larvae construct silken webs which become covered
by coarse pellets of frass (insect wastes). The larvae feed
within the nest, clipping off pine needles and pulling them
into the nest. Several (1-14) larvae may occupy a single nest.
Pupation occurs in the soil; overwinters as an adult. |
Number
of Generations |
3 or 4
generations per year. |
Signs
of Infestation |
Loss
of foliage Balls or lumps of coarse frass (dark pellets) on
stem or branches |
Control |
Natural
enemies, especially insect parasites, usually keep webworm population
at low levels. Promote tree vigor and health to aid in the recovery
from webworm defoliation. Handpick and destroy the nests and
larvae. Use an approved insecticide; however, most times an
insecticidal treatment is not necessary. |
Bulletin No. 196-A | Printed October, 1983 | Contact the
Forest Health Section 
