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Colaspidema atrum (Olivier)
Insecta, Coleoptera, Chrysomelidae .

Lucerne beetle

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

- Adult: shiny black body, hemispherical, 4 to 6 mm in length; head broad (*) . Once the female is ready to lay, her abdomen is distended by the eggs, which raise the elytra and appear as an orangy mass.
- Larva: 1.25 mm after hatching, elongated, orangy yellow. Pigmented plates bearing bristles grow during later instars, then covering the larva which becomes dark once its development is complete (*) .
- Eggs: yellow, 1 mm long, agglutinated in a yellowish mucilage in groups of 20 to 80 (*) .

- The lucerne beetle develops essentially on lucerne but can also live on clover.
- Adult: not very active, it walks about and feeds on leaves of the host plant. It acquires sexual maturity directly it emerges, in spring, and mates at once. Laying begins slightly after, on the leaves or on the ground.
- Egg: development lasts 12 to 15 days according to temperature.
- Larva: directly it has hatched, it attacks the leaf parenchyma and progressively eats all the lamina, leaving only the central vein. Development lasts 18 to 20 days during and induces several moults. It then leaves the plant and buries itself deeply in the ground (10 to 15 cm), builds itself a small cell and pupates.
- Pupation lasts about 10 days.

[R]Life Cycle
- 1 annual generation, probably a partial second generation in autumn.
- The immature adults which have hibernated appear progressively in April. Larval development occurs in May and June. The newly formed adults remain in the pupal cell from the summer to the next spring.

Damage due to the larval feeding is of great concern on the second lucerne crop (*) .

[R]Common Names
DE: Négril ES: Gusano negro, Cuca FR: Négril IT: Crisomelide nero della medica PT: Negrilho GB: Lucerne beetle

[R] Images

  1. Colaspidema atrum Olivier (Coutin R. / OPIE)
    Adult at rest on leaflet of alfalfa
  2. Colaspidema atrum Olivier (Coutin R. / OPIE)
    Egg-laying occurring on the upper side of a leaflet
  3. Colaspidema atrum Olivier (Coutin R. / OPIE)
    Larva on leaflet of alfalfa
  4. Colaspidema atrum Olivier (Carré S. / INRA Lusignan)
    Larvae on damaged alfalfa plants

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