Insecta, Diptera, Anthomyidae .
Description, Biology, Life Cycle, Damage, Common Names, Images
- Host plants: the brassicas and particularly radish, Horse-radish, turnip, cabbage, cauliflower; chicory, charlock and wild radish are also attacked.
- Egg: laid on the ground surface. Development lasts 10 days at 15░C.
- Larva: it gnaws the cortical tissue of the roots (*) and sometimes penetrates the basal part of the leaves of white-heart cabbage.
- Puparium: at a depth of 5 cm in the ground.
- 1 generation per year in northern countries (Denemark, Germany).
- The adults appear at intervals from July to September; the eggs are laid in August and September. The larvae which hatch at the beginning of September complete their development 30 to 40 days later. They pupate in the ground and hibernate.
The damage is invariably substantial.
- On the root-vegetables, the larvae form galleries which can reach up to the petiole of the leaves and render the vegetable unsuitable for consumption (*) .
- On the plants with woody roots, the galleries are limited to their peripheral parts, sometimes separating the extremity of the tap-root from the underlying roots. When the attack is on a massive scale, the plants cease to grow, assume a leaden taint and lack turgescence; gradually, they turn yellow and die. In cases less severe, the growth of the plants is very much slower than normal.
- In addition, the presence of galleries allows moulds to develop which attract saprophagic Diptera.
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