Arachnida, Acari, Tetranychidae .
Description, Biology, Life Cycle, Damage, Common Names, Images
- Associated with hornbeam (Carpinus) in the northern regions, but, in southern Europe, this mite has gradually invaded the vine.
- Adult: the winter females congregates to spend winter under the bark of the vinestock. When the 1st leaf appears, the mite is already in full activity, it feeds for about 10 days and begins to lay eggs when the shoots are between 3 to 5 cm long; average fecundity, 30 to 50 eggs.
- In summer, the hornbeam mite remains situated on the underside of the leaves, along the veins, and feeds on the cellular sap (*) .
The females spin fairly abundant but thin webs which ensure the protection of colonies against predators. Longevity of the female: 12 to 30 days depending on the temperature and the physical state of the foliage.
- Egg: development period, about 5 days at an average temperature of 23°C.
- Larva and nymph: includes several moults, the period of development is 7 days at 23°C.
- The number of generations varies from year to year with an average of 5 to 6.
- In southern regions, resumption of activity occurs as early as mid-April; the overwinteried females feed on young leaves (*) derived from the buds and the laying of eggs continues until the end of May. Generations then follow each other until the end of the season.
- Feeding damage leads to the drying up of numerous buds. Later, the hornbeam mite may cause the drying up of grape flowers or the loss of their pollen.
- Early infestations of the mite are particularly harmful to the plant which cannot open its buds normally, even when mite numbers are low.
- In summer, the attacks cause the appearance of spots along the veins (red for the red vine-plants and brown for the white vine-plants) which end up by invading the whole lamina, apart the veins (*) . The virtual prevention of photosynthesis leads to a reduction in the harvest, ripening delays and lowering suger content of the grapes representing a loss of 1 to 3° of alcohol.
HYPPZ on line : Species (scientific name), Pests (common names), Glossary, Crops.