Yellow Woollybear
Spilosoma virginica
Yellow woollybear larva with light coloration.
Yellow woollybear larva with dark coloration.
Yellow woollybear cocoon.
Yellow woollybear adult.
Yellow woollybear foliar damage on vegetables.
Skeletonized foliage caused by yellow woollybear feeding.
Hosts
- Field-grown hemp
- Many vegetable crops
- Various weeds
Description
Larvae are densely-haired caterpillars, though not as dense as other woollybear caterpillars, and range in coloration from rust-colored brown, yellow, to white. Adult moths have a white body and wings with black spots. Eggs are small, yellowish, circular. and laid in masses on leaves. Pupae are covered by a mix of silk webbing and hairs from the larvae.
Life Cycle
Egg | Larva | Pupa | Adult
- 2-3 generations per growing season.
- Overwinter as pupae within cocoons amongst soil debris.
- Adults fly from spring through fall, laying egg clusters on host foliage.
- Larvae feed gregariously at first, then begin to distribute by walking to other host plants.
- Pupation occurs in soil debris.
Damaging Lifestage(s): Larva
Damage Symptoms
Young larvae feed gregariously, and can skeletonize foliage. Older larvae are found alone, and chew irregular holes in leaves. Often, caterpillars move around readily on and between plants, causing distributed leaf damage.
Time for Concern
Summer to mid-Autumn
When and Where to Scout
- Look for egg clusters on leaf surfaces and the fuzzy larvae starting in midsummer.
- Larvae can also be found on soil surfaces in search of food.
Threat Level
Low. If present, hemp damage is likely minimal and insignificant to crop yield.
Occurrence in Utah
This insect occurs in Utah, but has not been identified as a pest in Utah hemp. It has been seen damaging hemp in neighboring states.
Management
- Keep crop area weed-free.
- Hand-pick and destroy larvae.
When to Consider Treatment
Manage if larval numbers and damage are high. Damage is focused on leaves and distributed over the plant, and plants can typically sustain damage. Large migrations of larvae into a hemp field may warrant management efforts.
Look-alikes
Saltmarsh caterpillar
Photo Credits
- Light yellow woollybear larva/cacoon/damage - Whitney Cranshaw, Colorado State University, Bugwood.org
- Dark yellow woollybear larva - David Cappaert, Bugwood.org
- Adult - Royal Tyler, Pro Pest and Lawn Store, Bugwood.org
- Skeletonized foliage - Daren Mueller, Iowa State University, Bugwood.org