Description, Biology, Life Cycle, Damage, Common Names, Images
- Host plants: crane flies are seen in summer on marshy ground, on grass in fields and on lawns. Highly polyphagous, the larvae attack various crops: Gramineae, field crops (turnip, etc.), vegetable gardens, peas, potato.
- Adult: flies in the morning and at nightfall in humid locations and mates several times. The eggs are dropped to the ground during flight or when the cran efly lands, on grass fields or weedy soils. Fertility: 300 to 400 eggs.
- Egg: embryonic development lasts approximately 15 days and requires high humidity.
- Larva: the young larvae feed on humus and vegetable waste matter which is more or less rotted. It is still small in size (1.5 mm) at the start of winter. Highly resistant to cold, it overwinters near the surface of the ground without diapause them becomes active once more in the spring. It digs underground galleries open to the air allowing it to emerge at night. It devours germinating cereal seeds in spring, the roots of Gramineae (*) and some aerial parts of young plants, in the collar area. Once growth is completed, it pupates in the soil.
- Pupa: development, approximately 3 weeks (*) .
-1 generation per annum for T. paludosa, the most harmful and widespread crane fly in Northern Europe, the larvae of which can cause severe damage from January to May, the adults flying from July, numbers reaching a maximum in September.
- 2 generations per annum for T. oleracea a more southerly species. Favoured by the climate, the larvae of this species continue to grow during the winter and become fully developed in March. The adults fly in April, a second generation in October.
- In permanent grassland, plants die in patches following severing of the stems; the tufts becoming sparse and yellowed.
- Seeded grassland is especially vulnerable when the seedlings push through the soil: the aerial parts of gramineae and cereals are devoured when they are 1 to 2 cm in height.
- Winter cereals, wheat and barley, can disappear from December: the underground part of the stem is cut, the plants yellow and die. Germinating spring cereals can be devoured from January onwards and the damage becomes more severe in spring.
- Shoots of peas and potato plants are devoured underground.
HYPPZ on line : Species (scientific name), Pests (common names), Glossary, Crops.