The Hawaiian beet webworm is a small brown moth crossed by bold white bands, found across the warmer parts of the world. Its caterpillars chew the leaves of spinach, chard, beets, and amaranth, so vegetable growers know it as a late-season pest. It's also called the beet webworm moth.
Appearance
- Appearance
- A small moth with a wingspan of about 7/8–1 in (22–24 mm). The wings are brown with white bands, and the abdomen is banded white too.
Look-alikes
In the Hawaiian beet webworm the main white band across the forewing is one broad, unbroken band on dark brown. In the spotted beet webworm that band is weak and split into two pieces, and the wings are a grayer brown with dark mottling.
Why they get mixed upBoth are small brown moths with white wing bands found in the eastern U.S., and both feed on beet-family plants.
Where it lives
- Typical habitats
- Vegetable fields
- Weedy patches
- Gardens
- Range
- Worldwide in warm regions. In the U.S. it occurs across the warmer parts of the country, and moths drift north in late summer, so growers in the Northeast mostly meet it in early fall.
- Preferred conditions
- Adults are easy to find in weedy patches, especially those with pigweed or galinsoga. They hide under leaves and fly up when disturbed.
Behavior
- Diet
- Caterpillars feed on plants in the amaranth and goosefoot families, plus some beans and nightshades. Crops include spinach, chard, beets, sugar beets, and amaranth; weed hosts include pigweed and lamb's quarters.
- Activity
- Adults are strong fliers known for long-distance migration.
Life cycle
- Reproduction
- Eggs are laid on leaf undersides near the midrib, and pupae form in the soil inside a cocoon coated with soil particles. The whole life cycle takes about 30 days.
- Larva
- Caterpillars are grayish green with a dark line down the back and grow to about 3/4–1 in (19–25 mm). They turn pinkish just before pupating. Young ones scrape the leaf underside, leaving clear "windows"; older ones hide in leaves rolled or tied with silk.
- Caterpillar food plants
- Spinach, chard, beets, amaranth, pigweed, and lamb's quarters, among others.
Conservation
- IUCN Red List
- NENot EvaluatedNot yet assessed
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