VOL I - PART IV STORAGE, TEXTILE & HYGIENE

Descriptions, food preferences, biology and significance of the major food storage, textile/fabric and poor hygiene pest moths

Grain - granella on a sticky trap in a food factory – see p 87

The following are included in this part of the handbook: Warehouse moth/Tobacco moth Ephestia elutella 79 Tropical warehouse moth Ephestia. cautella 82 Mediterranean Flour /mill moth Ephestia. kuehniella 84 Grain moth Nemapogon granella 86 Angoumois grain moth Sitotroga cereallella 88 Rice moth Corcyra cephalonica 90 Meal moth Pyralis farinalis 92 Indian Meal moth Plodia interpunctella 94 White-shouldered house moth Endrosis sarcitrella 96 Brown house moth Hofmannophila pseudospretella 96 Clothes moths Tinea spp 98 Small ermine moths Yponomeuta spp 100 Codling moth Cydia pomonella 102 Brown-tail moth Euproctis chrysorrhoea 104

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1. Warehouse Moth Ephestia elutella Family Phycitidae (Tobacco Moth)

Adult : when resting: 7-10 mm long; open wing span: 12 - 18 mm. A small greyish-fawn moth with an indistinct pattern of two bands across the front wings. The wings and body covered with scales (as with all ), which rub off with age.

Typical indistinct wing markings : 10-15 mm long. Creamy white: brown head capsule with darker brown body speckles and markings. 5 pairs of abdominal prolegs, including the “anal claspers”

Food preferences: Whole cereal grains, cereal products, oilseeds, cocoa beans, dried fruits, Larva with silk webbing edible nuts, , manufactured chocolate products, etc, and tobacco, the latter giving it its alternative name, the tobacco moth.

Life history: The adult moths mate within a few hours of emergence from the pupae. Most of the eggs are laid in the first four days of life, generally scattered around and amongst the food for the resultant larvae. The larvae moult 5-6 times, and produce copious amounts of silk “webbing” continuously during their wandering over raw and processed food materials.

The mature larvae migrate from the food and spend their winter months (diapause) in silken cocoons created often at the first horizontal crack in the factory or warehouse wall,. They rest as larvae and pupate during the following spring. Thus emergence of adults is generally annual, in summer. In warm climates there can be almost continuous breeding and development, with no noticeable diapause

Bionomics:

Temp Days spent as Duration of life cycle °c egg larva pupa adult weeks 20 10-14 80-200 14-21 10-30 26 9 8-13

Average rate of increase: x 15 per month Number of eggs: 7-360

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Conditions for development:

Temp °c Relative humidity % min max. optimum min max. optimum 10 25 30

Habits and importance: Almost cosmopolitan now, but probably of Old World origin. It has been present in Britain since the early 1800s; E elutella is particularly found in temperate zones.

This is one of the most important warehouse pests in UK, commonest in the south, but also found in Scotland. It is seldom imported, but has been found on tobacco consignments from the tropics (it is one of only two species able to develop on a diet of up to 5% nicotine!).

Adult moths are to be seen flying, mainly at dawn and dusk, in premises from mid- May to early Sept- ember with a peak of activity in early July.

Adults do not feed on solid food. Larvae, in addition to consuming food, contaminate it with considerable quantities of silken webbing and excreta.

Adult moth with good wing markings!, and larva with clear black speckles

The species is cold-hardy: it needs moderate relative humidities and thrives at moderate temperatures – ideal in the UK!.

Cacao moth, at rest, wings folded

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Sacks sheeted by elutella larval webbing

Newly hatched male sitting on cocoon The natural silk production by moth larvae is a very noticeable feature of infestations by this species. As the fully developed larvae migrate off their foods, they trail single strands of silk. En mass, this produces thick, opaque sheets of tough silk, covering sacks and pallets, and sometimes warehouse floors.

The picture on the right is evidence of an early moth infestation. An adult moth laid eggs on a complete Ephestia elutella damage and contamination walnut shell. The tiny, newly- hatched larvae entered some of the walnuts via the soft micropyle, causing a serious damage and contamination internally. Of course, as the larvae developed, they became too large to exit via the same route, and thus died, either as larvae, or pupae, or in a few cases as newly-emerged adult moths – all trapped inside the very hard walnut shells.

Elutella larvae & pupae dead in walnuts in shell

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2. Tropical Warehouse Moth - Ephestia cautella Family Phycitidae

Adult : When resting: 7-10 mm long; open wing span: 12-18 mm. Small greyish moth with pattern of 2 bands across fore-wings. The outer band is very obscure; the inner band is dark and straight with pale band. on its inner edge. However, the pattern is often difficult to see as scales rub off with age and activity – see pictures below

Mature larva : 12-14 mm long. Creamy white with brown head capsule and dark brown body speckled markings. 4 pairs of abdominal prolegs plus one pair of cautella larva with clearly speckled cuticle “anal claspers”

Food preferences: Cereals, groundnuts, palm kernels and other oilseeds, cocoa beans, spices, feeding stuffs, bones, dried fruits, edible nuts.

Life history: The adult moths pair shortly after emergence and egg laying starts 24 hours later. Most of the eggs laid in first four days of life.

The young larvae move freely through the food, contaminating it with webbing and frass. They feed until mature then wander over the foodstuffs, but seldom migrate in numbers (cf. E. elutella ). They often pupate in or on the foodstuffs after spinning a thick silken cocoon. There is little indication of diapause in E. cautella .

Bionomics:

Temp Days spent as Duration of life cycle °c egg larva pupa adult weeks 15.5 15 - c20 20 25 4 30 8 c10-15 6 30 3 20 5 c4-7 4

Average rate of increase: x 50 per month Number of eggs: 100-350

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Conditions for development:

Temp °c Relative humidity % min max. optimum min max. optimum 15.5 36 30-32 25 100 70-80

Habits and importance : Of Old World origin - possible Western Asia, but now cosmopolitan - spread throughout the world by commerce. First recorded in England in 1873 and found in all suitable environments before the end of the nineteenth century.

This is the commonest moth pest imported into Britain. It is established only to limited extent in Britain in unheated premises, but is found in food, chocolate and confectionery factories where a fairly constant warmth is available.

Adult moths avoid strong light and tend to rest in dark places during daytime. They fly mainly at dusk and dawn, usually from 1.5 to 3 metres height.

The species is moderately cold hardy. It requires high temperatures and moderate relative humidities.

Beautifully marked wings – they’re not always as clear as this – see below!

Scales lost from the wings, amongst the sticky dried fr uit

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