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Haplodiplosis marginata (von Roser)
Haplodiplosis equestris (Wagner)

Insecta, Diptera, Cecidomyiidae .

Saddle gall midge

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

- Adult: about 4.0-4.5 mm long; hairy; yellowish; thorax dark brown; abdomen red (*) .
- Larva: about 5 mm long; whitish and later orange-red to red; body divided into 14 distinct segments; sternal spatula situated ventrally on 1st thoracic segment; apodous; no conspicuous head capsule.

This insect feeds on several cereal species, the most frequently affected being wheat, barley, rye and, in places, oats. It also attacks other Gramineae, especially couch grass (Agropyron repens) and species of the genera Elymus and Lolium.
- Number of eggs laid: about 200.
- Duration of egg development: 7 days at a temperature of 18°C.
- Duration of larval development: 6-8 days.
- Pupation: 6-8 days at a temperature of 18°C.

[R]Life Cycle
- There is only one generation per year.
- Adults emerge from early May to mid-June, when the temperature of the upper layer of the soil reaches about 18°C.
- Females lay eggs on the upper surface of leaves along the veins, forming egg clusters.
- After hatching, larvae move down within the leaf sheaths to reach a stem node which they puncture, thus causing the formation of characteristic transverse swellings (*) . After reaching their full size in June or May, larvae penetrate the soil to a depth of 6-10 cm and enter a state of diapause. In the following spring, 10-20 % of larvae remain in diapause for one more year, the rest pupating in the superficial layers of the soil.
- Following wet springs, this insect is particulary numerous.

Parts of the stem situated above the node become swollen (*) . Internodes remain short and damaged parts can be broken easily. Affected ears mostly remain in the sheaths and produce atrophied grains.
Severe damage caused to plants at the edge of fields is typical of this insect.

[R]Common Names
DE: Sattelmücke ES: Cecidomido del trigo FR: Cécidomyie des tiges de blé IT: Cecidomia a sella delle graminacee PT: Cecidomídeo dos caules do trigo GB: Saddle gall midge

[R] Images

  1. Haplodiplosis marginata (von Roser) (Coutin R. / OPIE)
    Female about to lay eggs on wheat
  2. Haplodiplosis marginata (von Roser) (Coutin R. / OPIE)
    Affected stems The sheath has burst and the stem is distorted.
  3. Haplodiplosis marginata (von Roser) (Coutin R. / OPIE)
    Larvae on stem On the right, a part of the sheath has been removed to show the larvae. On the left stem, 2 characteristic saddle-shaped outgrowths (galls) formed where the larvae are present.

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