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Acrolepiopsis assectella Zeller
Acrolepia assectella

Insecta, Lepidoptera, Plutellidae .

Leek moth, Onion moth

Description, Biology, Life Cycle, Damage, Common Names, Images

- Adult: wingspan 16 to 18 mm. Head reddish; antennae, thorax and abdomen brownish. Narrow, rectangular fore wings, greyish-brown dotted with blackish marks and presence of white marks on lower edge. Narrow hind wings, light grey, much fringed (*) .
- Larva: 10 to 12 mm. Head, thorax and legs yellow. Abdomen pale green with 8 black spots per segment: 4 lateral and 4 dorsal each bearing a seta.
- Cocoon: fusiform, loosely woven, attached to the leaf, scape or flower stems (*) .

- Host plants: mainly leek and onion, but able to develop on all Allium crop species.
- Overwintering: as adult in plant debris; occasionally the pupa will also overwinter, although this is rare.
- Longevity of females: 6 weeks.
- Fecundity: approx. 100 eggs deposited on centre of inflorescences or on the leaves (*) .
- Eggs: time until hatching, 4 to 6 days in spring, and 8 to 11 in October.
- Larva: development duration, 15 days at 25░C; 5 instars.
- Pupa: developmental duration, 10 days at 25░C.
- The 1st generation, derived from overwintered adults, is small in number (especially if the winter was hard) and causes little damage. The summer generations are much more harmful.

[R]Life Cycle
- 2 or 3 generations per year in northern countries, and many more in the southern; the polyvoltinism being well adapted to climate.
- 1st generation adult: in winter, activity ceases due to the cold. Resumes (dusk and night) in March/April according to temperature. Egg-laying period lasts 20 days.
- Larva: mines the leaf on hatching (*) . 2 to 5 days later, it leaves the mine and burrows in between the central leaves.
- 2nd generation adult: appears at the beginning of July and oviposition occurs during July and August. Certain individuals emerge in October and give rise to overwintering adults, others remain in diapause until spring.

When the larva develops on 1st-year leek, it is the leaves that suffer. The lacerated appearance makes the leeks unfit for sale and the lesions facilitate rotting in (*) .
In onions, larvae remain in the leaf cone and cause partial desiccation. The damage in itself is of minor importance but, under unfavorable conditions, the onion ages too quickly and the larvae reach the more turgescent bulb and form galleries (*) . Harvested crops containing damaged bulbs will be rejected, because hidden damage cause losses in store and this can be a serious problem.
On seed-crop the larvae feed mainly at the base of the inflorescences and cause the flower stems to fall off in large numbers. Losses frequently reach 70 to 90% of the harvest.

[R]Common Names
DE: Lauchmotte, Zwiebelmotte ES: Polilla del puerro FR: Teigne du poireau IT: Farfalla del porro PT: Traša do alho-porro GB: Leek moth

[R] Images

  1. Acrolepiopsis assectella (Zeller) (Coutin R. / OPIE)
    Adult at rest
  2. Acrolepiopsis assectella (Zeller) (Coutin R. / OPIE)
    Leek damage The arrow indicates the attacked heart, in the process of withering.
  3. Acrolepiopsis assectella (Zeller) (Coutin R. / OPIE)
    Pupal cocoon The pupa is visible through the silk of the cocoon; the larval exuviae ejected from the cocoon remains attached.
  4. Acrolepiopsis assectella (Zeller) (Coutin R. / OPIE)
    Egg deposited on the leaf
  5. Acrolepiopsis assectella (Zeller) (Coutin R. / OPIE)
    Larva Gallery formed in a central leaf; the larva frass is moist.
  6. Acrolepiopsis assectella (Zeller) (Coutin R. / OPIE)
    Attacked onion

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HYPPZ on line : Species (scientific name), Pests (common names), Glossary, Crops.

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