Spiny and spotted bollworms

Earias vittella and Earias insulana Earias vittella (Fabricius, 1794); Earias insulana (Boisduval, 1833) · formerly or also: Earias fabia (E. vittella)

spotted bollworm (Earias vittella) · English, South and South-East Asia
Egyptian stem borer (Earias insulana) · English, Africa and the Middle East
चित्तीदार सुंडी (chittidar sundi) · Hindi, North India
دودة اللوز الشوكية (dūdat al-lawz ash-shawkiyya) · Arabic, Egypt and the Middle East

Spiny and spotted bollworms are small green moths whose spiny caterpillars bore into the growing tips of young cotton and okra, killing the shoots, and later into flower buds, flowers, bolls and okra pods. Damaged buds and young bolls drop, and bored bolls rot or open badly. Earias vittella is the main species in South and South-East Asia, and Earias insulana across Africa, the Mediterranean and the Middle East; both occur in South Asia.

Adult spiny bollworm moth (Earias insulana) with plain green forewings. Photo: AfroBrazilian, CC BY-SA 4.0, via Wikimedia Commons.

Type: Insect · Insect (moth; the caterpillars bore into shoots, buds and bolls)
Classification: Animalia › Insecta › Lepidoptera › Nolidae
Main crops: Cotton, Okra, Ornamentals
Found in: South Asia, South-East Asia and Oceania, Africa and the Middle East, Southern Europe
Chemical groups: IRAC 28, IRAC 5, IRAC 6, IRAC 22A (mode-of-action groups, not products)
Last reviewed: 2026-10-20

Spiny and spotted bollworms scientific name, order and family

The scientific name of spiny and spotted bollworms is Earias vittella and Earias insulana Earias vittella (Fabricius, 1794); Earias insulana (Boisduval, 1833), in the order Lepidoptera, family Nolidae.

Older or alternative scientific names: Earias fabia (E. vittella).

Where it occurs

E. vittella: South and South-East Asia to northern Australia. E. insulana: Africa, southern Europe, the Middle East and South Asia.

Region	Status
South Asia	Both species widespread
South-East Asia and Oceania	E. vittella
Africa and the Middle East	E. insulana widespread
Southern Europe	E. insulana present

Symptoms and identification of spiny and spotted bollworms

Spotted bollworm moth (Earias vittella), museum specimen showing the pale stripe on the green forewing. Photo: Komal et al. (2021), CC BY 4.0, via Wikimedia Commons.

The organism

Moths are small, with a wingspan of about 2-2.5 cm. E. vittella has green forewings with a broad white or cream stripe along the front edge; E. insulana has plain green forewings. Caterpillars grow to about 1.5-2 cm, are spindle-shaped and brownish with orange, cream and dark markings and rows of fleshy, finger-like spines. Eggs are tiny, blue-green and crown-shaped, laid singly on buds and leaves.

Signs in the crop, stage by stage

Crop stage	What you see
Vegetative stage	Shoot tips bored and drooping, then dying ('dead tops'); side shoots grow out and plants become bushy.
Squares and flowers	Flower buds and flowers bored with a round hole and droppings; bracts flare and buds drop.
Bolls and okra pods	Bolls bored and filled with droppings, rotting or opening early with stained lint; okra pods bored and deformed, unfit for sale.

Life cycle of spiny and spotted bollworms

Life cycle of Spiny and spotted bollworms — diagram drawn by Laisha from the stages below. Durations depend on temperature.

Females lay eggs singly on shoot tips, buds, flowers and young bolls. Caterpillars bore in soon after hatching and move from one fruiting part to another. Mature caterpillars spin a boat-shaped, brownish silk cocoon on the plant or on fallen buds and bolls, and pupate inside.

Stage	Duration	Notes
Egg	About 3-4 days	Single, on young growth.
Caterpillar (5 instars)	About 10-16 days	Bores into shoots, buds and bolls.
Pupa (in boat-shaped cocoon)	About 7-10 days	On plants or fallen parts.
Adult moth	About 1-2 weeks	Lays 200-400 eggs.

Temperature

Egg to adult takes about three to four weeks in warm weather; populations rise during warm, humid periods.

Generations

Many overlapping generations; continuous where okra and other hosts are available year-round.

Conditions that favour it

Warm, humid weather; okra and other mallow hosts grown near or before cotton; ratoon cotton and weeds; and loss of natural enemies after broad-spectrum sprays.

Economic threshold level (ETL)

There is no single international threshold. South Asian programmes use action levels based on the percentage of damaged shoots, buds or bolls, or caterpillars per plant, which differ between states and countries; check with your local extension service.

Thresholds are local. They depend on crop price, control cost, variety and natural-enemy activity, so use the figure your local extension service publishes where one exists.

Damage and yield loss from spiny and spotted bollworms

Shoot damage delays young crops; loss of buds and bolls reduces cotton yield, and bored bolls give stained, low-grade lint. In okra, bored pods are unmarketable, and losses can exceed half of the crop where unmanaged.

Monitoring

Check shoot tips, buds and young bolls on a set number of plants weekly and count damaged parts.
Collect and inspect fallen buds and bolls for caterpillars.
Use pheromone traps where lures for Earias species are available.

How to control spiny and spotted bollworms (integrated management)

Control works best as a sequence: prevent, monitor, then act only when a threshold or a risk forecast says so, using the least disruptive option that works.

Cultural control

Clip and destroy damaged shoot tips early in the season; collect and destroy fallen buds and bolls.
Remove malvaceous weeds and ratoon cotton; avoid growing okra continuously next to cotton.
Destroy crop residues after harvest so that pupae do not carry over.

Biological control

Egg parasitoids (Trichogramma species, released in many programmes), larval parasitoids, predators such as spiders and lacewings, and Bacillus thuringiensis help control Earias caterpillars.

Host resistance

Bt cotton (expressing Cry1Ac and related proteins) gives good control of Earias species; some okra varieties with smoother pods are less attacked.

Chemical control of spiny and spotted bollworms — by mode-of-action group only

Laisha names chemical options only by their resistance-committee mode-of-action group (IRAC for insects, mites and nematodes, FRAC for fungi, oomycetes and bacteria, HRAC for weeds), never by active ingredient or product. What is registered differs by country and changes over time; the label and your local plant-protection authority decide what may be used, on which crop, at what rate and with what pre-harvest interval.

Sprays target eggs and young caterpillars before they bore in. What is registered differs by country and changes over time; follow the label and your local plant-protection authority.

Scheme	Group	Mode of action	Notes
IRAC	28	Ryanodine receptor modulators (diamides)	Rotate.
IRAC	5	Nicotinic acetylcholine receptor allosteric modulators, site I (spinosyns)	Selective.
IRAC	6	Glutamate-gated chloride channel allosteric modulators	Rotate.
IRAC	22A	Voltage-dependent sodium channel blockers (oxadiazines)	Rotate.

Resistance management

Rotate groups between generations, avoid calendar spraying, and follow refuge rules with Bt cotton.

Look-alikes and how to tell them apart

Cotton bollworm — Larger caterpillars without fleshy spines, making larger holes in bolls.
Pink bollworm — Pink caterpillars inside bolls and rosetted flowers, with tiny exit holes.
Cotton boll weevil — Legless white grubs inside squares with sealed punctures; found in the Americas.

Host range

Cotton and okra are the main hosts; also hibiscus, roselle and other mallow-family plants and weeds such as Abutilon and Sida species.

What is still uncertain

The relative importance of the two species differs between regions and seasons.
Thresholds were developed mainly in South Asia.

Grow guides for its host crops

How to grow the crop well is the first line of defence. Laisha's free grow guides cover each crop from sowing to harvest:

How to grow Cotton How to grow Okra

Not sure this is what you are seeing?Ask Laisha: describe the symptoms or send a photo, and get a reasoned first read with what to check next — for your crop, your stage and your region.Ask Laisha

Sources

Earias vittella (spiny bollworm) datasheet — CABI Compendium. https://doi.org/10.1079/cabicompendium.20306
Earias insulana (Egyptian stem borer) datasheet — CABI Compendium. https://doi.org/10.1079/cabicompendium.20307
Earias vittella (EARIVI) — EPPO Global Database. https://gd.eppo.int/taxon/EARIVI
Impact of transgenic Bt cotton on nutritional indices of spotted bollworm, Earias vittella — Phytoparasitica (Springer). https://doi.org/10.1007/s12600-016-0540-3
Effect of natural enemy Trichogramma chilonis against spotted bollworm (Earias vittella) — Pure and Applied Biology. https://doi.org/10.19045/bspab.2018.70081

Written by Laisha from the sources above, in its own words. This page is general reference, not a prescription: confirm identification locally and follow the label and your plant-protection authority.