Fried fly
| Fried fly | ||||||||||||
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Fritfly ( Oscinella frit ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Oscinella frit | ||||||||||||
| ( Linnaeus , 1758) |
The frit fly ( Oscinella frit ) is a fly from the family of the shoot flies .
features
The fritflies are black with yellowish limbs and red eyes.
Way of life
In Central Europe, the fried flies can be found in three generations. The spring form usually sits on the flowers of dandelions or winter rape . The frit fly prefers moist habitats. Important natural enemies are ground beetles ( Bembidion and Agonum ) and parasitic wasps . For more information see "Reproduction".
Reproduction
The females, optically oriented at a distance and olfactory nearby, fly to large sprouting grasses such as maize , oats or barley to lay their eggs. Here it lays several eggs along the leaf sheaths , the hatching larvae penetrate the heart, causing the heart leaf to wither. The pupation also takes place at the wolverine place. The second generation flies from June and mainly uses oats as an egg-laying place, whereby the eggs are laid loosely in the panicles . When the larvae eat , the ear becomes pale (white-nourished) and the grains wither.
The maize is damaged by the first generation, the eggs of which are laid on the underside of the leaves and the stems in April or May, depending on the spring weather. Maize plants with 1 or 2 leaves are preferred, even in the 3-leaf stage they are hardly attractive anymore. The 2.5–4 mm long maggots feed on the leaves that are still rolled up near the point of vegetation.
The third generation of the year flies in August to September and lays the eggs on various winter grasses. Around 60 host grasses such as maize, cereals (especially oats and barley), bluegrass, ray grass and red fescue are known for this species, other grasses are of little importance for humans.
Man and fried flies
damage
In the damage pattern, the leaves of the young plants show yellow, scarred, often longitudinally running injuries or deformities. Occasionally, the tips of two leaves stick together and do not unfold normally. Rows of holes running across the sheet are typical. Infested plants are often left behind and form side shoots.
The infestation and the resulting losses vary greatly depending on the year, sowing date and location. Losses of more than 10% are rare. Damage mainly occurs when development is delayed between emergence and the 10-leaf stage of the maize.
Combat
The control takes place indirectly through the promotion of the youth development of the affected plantations through appropriate choice of variety and optimal seedbed preparation. The direct control is carried out by insecticide granules applied during the sowing, which usually have a good effect against fries. A preventive use only against fried flies is rejected for ecological reasons.
The effectiveness of the approved sprays is less certain; they are used when the maize has 2 leaves. Control threshold: 6 eggs / 10 plants.
literature
- Christa Volkmar, Theo Wetzel: The frit fly and its control , Halle (Saale) 1977
- F. Häni, G. Popow, H. Reinhard, A. Schwarz, K. Tanner & M. Vorlet: Plant Protection in Integrated Agriculture , Agricultural Teaching Aids Center, Zollikofen Switzerland, 1988, 335 pp.