Fall Webworm - Nursery IPM

**Fall Webworm (Hyphantria cunea)**

Mostly visual concerns
Feeds within silken webs which encircle branches, twigs, and leaves
Similar web to eastern tent caterpillars
- Fall webworm makes webs at the tips of branches, and never leaves the protective webbing
When more food is needed, the boundaries of the web are extended
Larvae may feed for a few weeks before webs become apparent
Webs are most noticeable near the end of the larvae feeding periods
Pupate in late summer/early fall and overwinter in the soil
First generation is in late May and June, and is usually small, while the second generation can cause outbreaks
Caterpillars are pale yellow to greenish, with dark spots or stripes, covered in hairs, and either a black or red head
- When disturbed, exhibit a synchronized jerking motion
Leave behind frass and skeletonized leaves within the webs
Cause defoliation
Host plants: more than 100 species of trees
- Mulberry, ash, elm, linden, sweetgum, willow, walnut, hickory, oak, apple, other fruit trees

Natural predators: fall webworm is native, so has many natural predators and parasitoids to keep populations in check
Encourage beneficial insect populations
- Food and water sources
- Use less pesticides
Prune out nests
Prune out unsightly webs or rip them open with a stick or jet stream of water to destroy the caterpillars

Contact insecticides:
- Pyrethroids [3]: – thrins
  - Lambda-cyhalothrin, cyfluthrin
- Carbamates [1A]: carbaryl
Systemic insecticides:
- Chlorantraniliprole [28]
- Acephate (translaminar)
Considerations:
- Most will harm non-target species