Taupin (insect)

Description

The adult is a coleopter of lengthened form, with hard carapace and of dark color. Their body is usually tapered and measures from 1 to 3 cm length. The larva is thin, cylindrical, of color going from ocher to copper with a head brown dark. It has 3 pairs of legs and its posterior part ends in a short point chestnut. It reaches 3 cm length at the end of the cycle. The worms wire appreciate moisture and are sensitive to the dryness.

Biology

The evolutionary cycle hard from 3 to 6 years according to the species, and the larva nourishes itself actively during 2 to 5 years. In the usually infested zones, all the larval stages can be present at the same time during the season of vegetation. The developed larva usually transforms itself into nymph in the ground at the end of the summer or at the beginning of the autumn, to arrive at the adult stage in less than 3 weeks and to winter. The adults emergent of the ground spring or the next summer and couple themselves, after which the females are inserted with a depth from 2.5 to 15 cm in the ground and lay from 50 to 300 eggs. As the females fly with difficulty, the infestations are slow to be propagated from one camp to another. The eggs take from 3 to 4 weeks to hatch, and the new larva nourishes vegetable residues or roots of many cultures and bad grasses. The larvae are inserted and go up in the ground to adapt to the conditions of moisture, temperature and food. They winter generally in-depth not to be touched by freezing. They go back to spring when the temperature of the surface layer is of 10 °C. The larva of the last larval stage immediately starts the nymphose either, or in spring after having spent the winter with the shelter in the cabin.

Damage

The larvae of taupins appear especially the second year following the establishment of the garden. In spring, the larvae dig galleries in the potato seeds, the roots and the growths of growth. Later, during the season of vegetation, the worms wire nourish underground parts of potato, carrot, beet, onion, tomato, leek. They dig galleries 3 mm in diameter and 4 cm depth (smaller than those done by the white worms). The attacked plants die or are unsuitable with consumption. The larvae also attack the roots of salads, with the roots of the grasses and the young trees.

Means of fights

Preventive fight

- The first year of establishment of the garden, cultivate especially crucifères (cabbage, broccolis, cress), and to move these cultures the following years. - Protect their natural enemies: the mole, the shrew, carabes, birds such as the crows, starlings, thrushes.

- Bring of the manure or the compost to increase the resistance of the cultures.

Ecological fight

- The eggs are localized in the 5 to the first 10 centimetres of the ground of mid-May at the beginning of July. They are very sensitive to dehydration, they is thus recommended to carry out a two-prong crimping of the ground and to let dry

- The larvae of taupins appreciate the compact and wet grounds: work the ground several times in order to loosen it well, air it and drain it.

- Have the soft foods: insert carrots or potatoes cut into two in the ground, the cut face being to approximately 5 cm of depth. Control and destroy regularly the attracted larvae.

- To plow the ground late with the autumn to expose the worms to freezing and their predatory.

Chemical fight

If the preventive and biological methods of fight remain insufficient, there exist specific products for garden containing Diazinon or of Chlorpyriphos-éthyl to fight against the taupins. It should not nevertheless not be forgotten that these chemicals destroy all auxiliary fauna and thus pose in the long term problems of imbalance of the ground. It is important to intervene at the good moment: with the Printemp S (April, May) with the increase of the larvae or the beginning of the Fall (September) before the Hibernation of the larvae. These products act by ingestion and contact: they should be incorporated in the surface layer of the wet ground.

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