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Oscinella frit (L.), {Oscinella pusilla (Meigen)}
Oscinosoma frit

Insecta, Diptera, Chloropidae .

Frit fly

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

- Adult: black fly, length approximately 3 mm, width 1 mm (*) .
- Egg: elongated, whitish, 0.70 mm x 0.16 mm long.
- Larva: pale yellow, 4 mm long when fully developed.
This frit fly is very similar to the barley frit fly (Oscinella pulsilla Meigen, O. grossa Mesnil). The differences are not visible to the unaided eye; they concern the antennae and the colour of the tibia.

- Host plants: wild or cultivated Gramineae, rye grass, fescue, timothy and also, maize and winter cereals: oats, barley and wheat. Unlike O. frit, O. pulsilla does not attack oats and rarely, maize.
- Adults from larvae which have spent the winter in diapause in winter cereals, wild gramineae or seeds emerge in May. The female lays its eggs on young cereals in spring(*) . Minimum fertility, 25 to 35 eggs. The eggs of subsequent generations are laid at the base of leaves, on young ears or on the shoots.
- Egg: incubation lasts 3-4 days.
- On very young plants, the larva insinuates itself between the leaves, to the heart of the plant which is destroyed. Larvae from eggs laid on leaves enter the sheath and attack undeveloped flowers or on oats, the spicule peduncles. If the ears or panicles are attacked, the spicules are penetrated and the newly forming grains and flowers devoured.

[R]Life Cycle
-3 generations per annum, sometimes 4 under favourable weather conditions. Typically, the adults emerge in April-May, June-July and August-September. The larvae of the final generation overwinter and the pupa forms in April-May after a thermal shock of 11 to 12C.
- 2 generations for O. pusilla, sometimes a 3rd. The development of this species is longer than that of the oat frit fly and occasionally, there is no generation on the ears.

- At leaf stage 2 the central leaf wilts, yellows and dries up. If the plant is sufficiently vigorous it produces tillers, otherwise dies.
- On maize, the attack is manifested by deformation of the leaves (*) . The terminal bud can be destroyed, causing death of the plant or growth of non-productive tillers. Smut (Ustilago maydis) may develop on damaged leaves.
- Attacks on oats are common, those on barley or maize, rare.

[R]Common Names
DE: Fritfliege ES: Mosquita de la cebada y de la avena FR: Oscinie de l'avoine IT: Mosca dell'avena PT: Oscinela da aveia GB: Frit fly

[R] Images

  1. Oscinella frit (L.) (Moreau J.-P. / INRA)
    Adult on leaf of wheat
  2. Oscinella frit (L.) (Moreau J.-P. / INRA)
    Eggs Laid on a small stem of wheat (arrowed).
  3. Oscinella frit (L.) (Coutin R. / OPIE)
    Damage to maize Affected stipe remains short.
  4. Oscinella frit (L.) (Coutin R. / OPIE)
    Damage to maize Growth is interrupted, terminal leaves are crinkled and new growth appear on the stem (arrowed).

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