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Autographa gamma (L.)
Phytometra gamma, Plusia gamma

Insecta, Lepidoptera, Noctuidae .

Silver y moth, Common silver y moth

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


[R]Description
- Adult: 40 to 45 mm wingspan. Brownish-yellow fore wings with, at their centre, a white spot resembling the shape of the Greek letter gamma. The hind wings are light brown, smoked at their periphery (*) .
- Larva: 40 to 45 mm, light green with 6 longitudinal whitish lines (*) . Small and yellowish head, narrow anterior third of the body. Provided with 2 pairs of abdominal prolegs and one pair of anal prolegs, it moves about as a span-worm (*) .
- Eggs: greyish white, flattened, they are deposited in bunches or singly on the underside of the leaves, generally, of wild plants or of certain cultivated plants.

[R]Biology
- Host plants: the larvae first attack the leaves of certain wild plants, then, in cultivated plots, the leaves of red beet, potatoes, cereals, flax, vegetables and even nursery plants.
- Adult: the moths, generally nocturnal, fly very rapidly, either alone or in small groups, sometimes in swarms which can be composed of millions of individuals travelling over hundreds of kilometers.
- Larva: the caterpillar is especially active during the night: it nibbles the lamina of leaves and cuts the leaf-stalks (petioles). During the day, it remains pressed against the underside of the leaves. Larval development lasts about a month.
- Pupa: the larva pupates in the folds of the leaves of the host plant (*) and the adults emerge 10 to 15 days later.

[R]Life Cycle
- The importance of the migrations leads to a geographical distribution of the species which differs considerably from season to season, so there is no distinct development cycle in any given place. The common silver y moth is common in North Africa and in the Mediterranean basin during winter; in summer, it occurs as far north as Scotland and Finland.
- The adults fly in the Paris region from the end of May to the beginning of June. A second flight takes place generally at the end of July.

[R]Damage
In years of swarming, colonies of thousands of individuals invade cultivated fields (red beet, potato, etc.). The older caterpillars are particularly voracious (*) . Such invasions enable the development of numerous natural enemies of the caterpillar, particularly certain viral diseases whose effect is such that the second generation is almost non-existant.


[R]Common Names
DE: Gammaeule ES: Noctuido gamma FR: Noctuelle gamma IT: Nottua gamma PT: Nóctua gama GB: Silvery moth, Common silver y moth

[R] Images

  1. Autographa gamma (L.) (BASF)
    Chenille The number of abdominal prolegs is reduced.
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  2. Autographa gamma (L.) (BASF)
    Attack on beet
  3. Autographa gamma (L.) Moth Landed on a Chrysanthemum.
  4. Autographa gamma (L.) Moth Feeding on Sedum.
  5. Autographa gamma (L.) Cocoon The silk, always very flimsy, allows the pupa to be seen.
  6. Autographa gamma (L.) Larva (Rasplus J.-Y. / INRA Versailles)

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