Helicoverpa armigera

Helicoverpa armigera (Hubner, 1805)
(one synonym : Heliothis conferta)
Corn Ear Worm, Tomato Grub, Tobacco Budworm, Cotton Bollworm
HELIOTHINAE , NOCTUIDAE

Don Herbison-Evans ( donherbisonevans@yahoo.com )
&
Stella Crossley

(updated 29 September 2008)

This Caterpillar is initially pale green, sometimes with black dots, and a pattern of thin dark lines running along the body, the lines being darker around the second and third segments.

In later instars , the dark lines become less conspicuous, and the black spots develop red areas around them. There is a good deal of variation in colour in this species. Lighter and darker forms of both Caterpillars and moths are known, for example, having white instead of black spots on the Caterpillars. The Caterpillar has posture when disturbed characteristic of a number of species in this family : it lifts its head and curls it under the front of the body. If even more disturbed, it lets go and drops, rolling into a spiral.

In the wild, it has been found on:

Annual Sowthistle ( Sonchus oleraceus, ASTERACEAE ),

but it is a serious pest internationally on various crops, including :

Sunflowers ( Helianthus annuus, ASTERACEAE ),

Zucchini ( Cucurbita pepo, CUCURBITACEAE )

Beans ( Phaseolus vulgaris, FABACEAE ),

Leeks ( Allium porrum, LILIACEAE ),

Cotton ( Gossypium hirsutum, MALVACEAE ),

Maize ( Zea mays, POACEAE ),

Plum ( Prunus domestica, ROSACEAE ),

Lemon ( Citrus limon, RUTACEAE ), and

Tomatoes ( Lycopersicum esculentum, SOLANACEAE ),

as well as ornamental plants and flowers, including:

Pinks ( Dianthus, CARYOPHYLLACEAE ),

Geranium ( Pelargonium x zonale, GERANIACEAE ).

The specimen pictured above was actually found on :

Lettuce ( Lactuca sativa, ASTERACEAE )

purchased from a supermarket in Bundaberg.

When fully grown (4 cms.) it pupates in a cocoon under the soil.

The adult moth emerges after between three weeks (summer) and six months (winter). It has brown forewings with a delicate darker tracery around a single dark mark on each wing. The hind wings are buff with a dark border which contains a light patch. The chemical identities of the sex attractant compounds for this moth (pheromones) have been elucidated.

(Specimen: courtesy of the Macleay Museum, University of Sydney)

The undersides are buff with dark submarginal bands on each wing, and each fore wing also has a black comma mark and a black full stop. The adults fly long distances, and these have been tracked by radar.

underside

The adult moths look very similar to those of the related species in the same genus : Helicoverpa punctigera. However, for Helicoverpa armigera

the Caterpillars have white hairs on the prothorax,

the Caterpillars have no dark triangles on the first abdominal segment, and

the moths have a pale mark in the black border of the hind wing.

The species is a pest world-wide:

Africa, including:

Cote D'Ivoire,
Kenya,
Tanzania,

Europe, including:

Finland,
France,
Germany,

Asia, including:

China,
India,
Nepal,

Australasia, including:

Tasmania, mainland Australia, and
New Zealand.

Tuvalu, 1991

In Europe, this species is often called the "Scarce Bordered Straw", but this name seems inappropriate in Australia where the Caterpillar is so common. Note that the species does not (yet) seem to have appeared in the Americas. In Australia, it is seldom found as far south as Melbourne. However, we regularly find it in Melbourne in ears of corn purchased from a greengrocer (that are presumably grown further north).

Unlike its relative: Heliocoverpa punctigera, it develops resistance to many insecticides. Attempts are being made to control the Caterpillar using :

artificial pheromones,

special chemicals such as Larvin (a combined ovicide and larvicide),

insecticides such as Fenvalerate synergised with Piperonyl Butoxide,

extracts from Neem tree ( Azadirachta indica, MELIACEAE ),

extracts from Southern Pea ( Vigna unguiculata, FABACEAE ),

extracts from Wild Groundnuts ( Arachis paraguariensis, FABACEAE ),

a Cypovirus ( REOVIRIDAE ),

a Granulovirus ( BACULOVIRIDAE ),

a Stunt Virus ( TETRAVIRIDAE ),

a Poxvirus ( POXVIRIDAE ),

the bacterium Bacillus thuringiensis ( BACILLACEAE ),

with Nematodes ( NEMATA ),