Old World Webworm
ExploreInsects
Old World Webworm
hellula undalis
The Old World Webworm (Hellula undalis), also widely known as the cabbage webworm, is a small moth belonging to the family Crambidae. Though the adults are modest and easily overlooked, their larvae are notorious in agricultural circles as highly specialized herbivores with a strong preference for plants in the brassica family, such as cabbage, broccoli, and radishes. This species is highly adaptable and thrives in warm, temperate, and tropical climates across Europe, Asia, Africa, and Australia. What makes the Old World Webworm fascinating is the larval survival strategy. They construct intricate silk webs over their feeding zones, which act as a protective fortress shielding them from environmental hazards, predators, and even chemical controls, making them remarkably resilient in their habitats.
Habitat: Found in agricultural fields, vegetable gardens, and cultivated croplands where cruciferous plants are grown.
Appearance
The adult Old World Webworm is a small moth with a wingspan of 1 to 2 centimeters. Its forewings are mottled grayish-brown, decorated with distinctive wavy, undulating pale-brown and dark-brown bands, while the hindwings are a uniform pale grayish-white. In its larval stage, the caterpillar is easily recognized by its creamy-yellow body adorned with five prominent, dark-brown longitudinal stripes and a shiny blackish-brown head capsule.
KingdomAnimaliaPhylumArthropodaClassInsectaOrderLepidopteraFamilyCrambidaeGenusHellula
Category
InsectsRarity
Common
Danger
1/5 · Very low
Snaps
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Interesting facts
Adult moths are strictly nocturnal and are highly attracted to artificial light sources, making them easy to spot around outdoor lamps at night.
The Old World Webworm caterpillars can ruin an entire cabbage harvest by eating the central growing tip, which prevents the cabbage head from forming.
Their silk webbing acts like a raincoat, shedding water droplets to keep the larvae dry during heavy downpours.
Special abilities
Ability
Silken Fortress
Larvae spin dense silk webs over their feeding sites, protecting themselves from predators, rain, and desiccation.
Ability
Apical Boring
Caterpillars can bore deep into the growth buds and stems of host plants, effectively hiding from external chemical treatments.
Ability
Rapid Development
In warm climates, this species can complete its entire lifecycle in under a month, allowing it to produce multiple generations in a single season.
Measurements & details
- Length
- 1-2 cm
- Wingspan
- 1-2 cm
- Top Speed
- 5 km/h
- Clutch Size
- 40-150
- Incubation
- 3-7 days
Diet & Feeding
The larvae feed primarily on the leaves, buds, and stems of cruciferous plants, while adults feed on flower nectar.
Age differences: Caterpillars feed strictly on plant tissues, while the adult moths feed on flower nectar.
Primary Foods
- Cabbage (Brassica oleracea)
- Radish (Raphanus sativus)
- Mustard greens (Brassica juncea)
- Canola (Brassica napus)
Foraging Method
- Grazing
Ecological connections
host plant
Cabbage
Brassica oleracea
The caterpillar feeds heavily on cabbage leaves, often destroying the apical bud of the plant.
parasite
Braconid Wasp
Bracon hebetor
This parasitoid wasp attacks the larvae of the webworm, laying eggs inside them to develop.
eaten by
Paper Wasp
Polistes humilis
A common predatory wasp that feeds on cabbage webworm caterpillars in garden ecosystems.
Traits
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Also known as
No aliases listed yet.
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Safety
Danger
1/5 · Very low
No special safety notes yet.
Frequently Asked Questions
How to identify Old World Webworm?
The easiest way to identify Old World Webworm is to use the Snappit nature identifier app.
How long is Old World Webworm?
1-2 cm
What is Old World Webworm's wingspan?
1-2 cm
How fast can Old World Webworm move?
5 km/h
What does Old World Webworm eat?
The larvae feed primarily on the leaves, buds, and stems of cruciferous plants, while adults feed on flower nectar.
Where is Old World Webworm usually found?
Found in agricultural fields, vegetable gardens, and cultivated croplands where cruciferous plants are grown.
How does Old World Webworm hunt?
Grazing
How many eggs does Old World Webworm lay?
40-150
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