PESTS OF LINSEED :: Major Pests :: Linseed Gall-Midge

1.  Linseed Gall-midge: Dasineura lini (Cecidomyiidae: Diptera)

Distribution and status: Serious in Andhra Pradesh, Madhya Pradesh, Bihar, Uttar Pradesh, Delhi and Punjab.

Host range: Linseed  

Bionomics: The adult of this gall-midge is a small orange fly. The female lays 29-103 smooth, transparent eggs in the folds of 8-17 flowers or in tender green buds, either singly or in clusters of 3-5. The eggs hatch in 2-5 days. Just after emergence, the larvae are transparent, with a yellow patch on the abdomen. They pass through four instars in 4-10 days and when full-grown become deep pink and measure about 2 mm in length. The full-grown maggots drop to the ground, prepare a cocoon and pupate in the soil. The pupal period lasts 4-9 days. A generation is completed in 10-24 days. There are four overlapping generations during the season.

Damage symptoms: Damage is the result of feeding by maggots on buds and flowers. Consequently  no pod-formation takes place.

Management

1. The adult flies can be killed by using light traps. The flies are also attracted in day-time to molasses or gur added to water.
2. As the incidence of this pest is more on the late-sown crop as compared with the nonnal-sown crop, the practice of nonnal-sown crops should be adopted if possible.
3. Dust 5 per cent carbaryl 15-20 kg/ha or spray carbaryl 50 WP 1.125 kg/ha in 600-750 L of water/ha.
4. Conserve larval parasitoids viz., Systasis dasyneurae Mani (Miscogasteridae), Elasmus sp. (Elasmidae), Eurytoma sp. (Eurytomidae), Torymus sp. (Torymidae) and Tetrastichus sp. (Eulophidae).