Stored Product Moths

Characteristics

Two pairs of well developed membranous wings, with few cross veins; clothed with broad scales; generally suctorial mouthparts; metamorphosis complete with egg, larval, pupal and adult stages; larvae frequently have eight pairs of limbs.

 Mediterranean flour Moth

(Mill Moth/Flour Moth) (Ephestia Kueniella)

20-25mm wing span: upper forewing: oblique irregular inner band spotted or streaked, lacking pale band along inner edge; outer band is obscure.

Distribution

Originated in Central America but now cosmopolitan. It is a particular problem in food mills, bakeries and occasionally even catering premises. One generation is usually produced, but in warm conditions adults will be present throughout the year when there may be 4-6 generations.

Significance

Larval webbing can cause serious blockages in food mills. The larvae eat holes in sifting silks and may also reach the millís finished products.

Life-Cycle

Mating takes place immediately after the adults emerge. Up to 350 eggs laid and these may be stuck to various foods by a sticky secretion.

The eggs hatch in 4-28 days to give white or pinkish larvae and spin silken tubes in which they live. After 3-5 moults the larvae are full grown and 15-19mm long. They then wander away from food and pupate for 7-16 days in dark corners of the building or machinery. In temperate climates these moths over winter as larvae but in contrast to other species, usually remain in the foodstuff.

Warehouse Moth

(Cacao Moth, Tobacco Moth) (Ephestia Elutella)

12mm wing span; upper forewing; well-defined, rather sinuate outer band on grey-buff back round.

Distribution

Widely distributed throughout temperate regions. It is rarely imported except on products from other temperate areas.

Significance

A Major pest of warehouses and more recently, retail premises. This species will infest cereals, fruit, shelled nuts, cocoa beans, fish, spices and tobacco. Moth infestations are especially serious where wheat and flour are stored in bulk, although they seldom infest goods, which are stored in silos.

Life-Cycle

Within 4 days of emergence, the female produces 100-150 eggs, which are laid in cracks and crevices. These hatch in 10-14 days to give larvae, which are creamy white with dark spots on their sides. They penetrate food, covering it

with webbing as they feed. In temperate climates larvae go through 4-5 moults to attain full growth of 12mm long. They then leave the food and search for 1-3 days for a dark place in which to spin a silken cocoon. They may stay in this state throughout the winter before pupating in April or May and emerging as adults in late spring. Under temperate conditions development takes from 82-206 days

Common Clothes Moth

(Tineola bisselliella)

10-15mm wing span;upper forewing: pale ochreous buff, unmarked.

Distribution

Common on animal products

Significance

Clothes moth larvae feed and cause the damage. Moths do not feed. Larvae feed on fur, skins, wool and leather. Fibres are bitten off and the loose ends discarded, thus destroying more commodity than is consumed.

Life-Cycle

Eggs are laid amongst fibres or scattered at random. Each female layís up to 160 eggs during a period of 2-3 weeks. During the summer these hatch in 4-10 days to give an active, white translucent larva. This grows up to 10mm in length and the head becomes darker in colour. Feeding tunnels may be constructed from silk. There are at least 5 moults. Larvae construct a tough cocoon in which they moult to produce a pupa up to 7mm long. The full cycle takes between 88-254 days depending on conditions.

Control of Stored Product Moths

The method and timing of control measures against moths, depends upon the species involved. The larvae are frequently difficult to reach because they are concealed in foodstuffs or the fabric of buildings and may be obvious only they migrate.

Assessment of infestation

Funnel trap may be used. These are usually constructed of plastic and incorporate a funnel system leading to a retaining chamber in which moths are trapped and killed using a toxic strip, water or detergent. They incorporate a pheromone lure and are particularly useful in dusty locations.

 Hygiene/Management

Spillages should be removed promptly and infested goods dealt with immediately either by fumigation or destruction. Uncontaminated products should not be stored in the vicinity of infested materials.

Insecticidal Control

In order to obtain the best results, insecticidal control measures should be integrated with good hygiene.