Insecta, Coleoptera, Chrysomelidae .
Description, Biology, Life Cycle, Damage, Common Names, Images
Oulema lichenis occurs most commonly on cereals, especially wheat. It also attacks wild Gramineae.
- Number of eggs produced: 100, 300 at the very most.
- Duration of egg development: 8-10 days.
- Duration of pupation: about 2 weeks in late July.
- The whole development, from the egg to the young adult, lasts about 34 days.
- There usually is 1 generation per year but 2 generations may be produced in the South and South-East of Europe depending on weather conditions.
- Adults overwinter under the leaves and other plant debris, partly in the soil. After leaving their shelter in the spring, they attack wild Gramineae and, from May onwards, cereals (winter barley and then winter wheat). Spring wheat is, in turn, also attacked.
- From mid-May, eggs (*) are deposited in rows on the upper side of leaves. Larvae infest winter wheat from ear emergence until the end of milky ripeness. In dry weather conditions, ear emergence may be prevented, thus hindering growth.
- Larvae pupate in a white cocoon on leaves, stems and ears (*) . After emerging in late June, young adults spread to late cereal fields or to wild Gramineae and shelter in late October.
- Egg-laying is favoured by high spring and summer temperatures, which lead to an increase in population numbers. In contrast, temperatures below 16 or 17°C in May-June and heavy rainfall cause the death of larvae and pupae.
- Spring feeding by adults causes characteristic damage, grazing away longitudinal sections from the upper section of the leaves. Larvae also cause such depredations. Young adults feed mainly on wild Gramineae, larvae feeding rather on the flag leaf of summer cereals and sometimes causing severe damage, with a reduction in yield of up to 60%.
- This species can transmit viruses from graminaceous plants to cereals.
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