Oscinella frit

(Oscinella frit )

(Oscinella frit ) is a fly from the family of Halmfliegen.

Features

The Fritfliegen are black with yellowish foot members and red eyes.

Way of life

In Central Europe the Fritfliegen are found in three generations. The spring form usually sits on the flowers of the dandelion or the winter rape. The frit fly prefers moist habitats. Important natural enemies are ground beetles ( Bembidion and Agonum ) and parasitic wasps. For more information, see " grain ".

Reproduction

The females fly to the removal of optically oriented and olfactory near, large sprouting grasses such as corn, oats or barley to lay their eggs. Here it lays along the leaf sheaths from several eggs, the hatching larvae penetrate into the heart, causing the heart leaf wilts. Pupation also takes place at the food place. The second generation flies from June and primarily uses oats as a nesting beach, where the eggs are loosely placed in the panicles. Through the feeding of the larvae the ear pale ( ear blight ) and the grains will wither.

The corn damages the first generation whose eggs are laid, depending on the spring weather in April or May on the lower leaf surface and stems. Corn plants with 1 or 2 leaves are preferred in this case, already at the 3- leaf stage are hardly more attractive. The 2.5-4 mm long maggots eat near the growing point at the still furled leaves.

The third annual generation flies in August and September, lays the eggs from a variety of winter grasses. Here are about 60 host grasses such as corn, grain (especially oats and barley), Kentucky bluegrass, red fescue and Raygräser for this type known, other grasses are of little importance for humans.

Man and frit fly

Damage

The pattern of damage the leaves of young plants have yellow on scarred, often extending in the longitudinal direction of injury or malformation. Occasionally the leaf tips of two leaves stuck together and not unfold normally. Typical are transverse to the sheet extending rows of holes. 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 place. Losses of greater than 10 % are rarely. Damage occurs mainly when the development between emergence and the 10 -leaf stage of the corn is delayed.

Combat

The fight takes place indirectly through the promotion of youth development of the affected plantations through appropriate choice of varieties and optimum seedbed preparation. Direct combat takes place through deployed in the seed insecticide granules, which usually have a good effect against Fritfliegen. A preventative use only against Fritfliegen is rejected on environmental grounds.

The effectiveness of approved pesticides is less secure, it operates when the corn has 2 sheets. Control threshold: 6 Eier/10 plants.