Tortrix viridana
Green oak ( Tortrix viridana )
The green oak ( Tortrix viridana ) is a butterfly (moth ) from the family of the winder ( Tortricidae ).
- 6.1 Notes and references
- 6.2 Literature
Description
The moths reach a wingspan of 16-24 millimeters. Their forewings are grass green to pale green and typical of the family, at the rear end square tapering. On the wing ends completes a white fringed hem. Their hind wings are light gray and also have a white hem. The head is yellow, the green chest and the abdomen gray.
The young caterpillars are ocher- gray to gray-beige and have dark heads. The older animals are gray-green. The larvae go through five stages of growth.
The eggs are perfectly round and about 0.7 millimeters wide. They are initially pale yellow and brown color later.
Similar Species
- Willow Kahneule ( Earias clorana )
Occurrence
The animals are found throughout the western Palaearctic distribution range of oak (Quercus spp.). They live in deciduous and oak forests and other areas that are overgrown with oak trees. They fly from May to in the summer.
Way of life
The females lay about 50 to 60 eggs on branches or leaves, preferably in the upper half of the tree crowns from. They will cover two eggs in pairs in a sticky mass together. On this mass of dust adhering and growing on algae are a good camouflage. The larvae hatch after overwintering in the next May They eat into already open buds, because they can not drill closed. The young larvae feed on young leaves, until the third instar they begin einzuspinnen leaves around it so eat them from the inside. The caterpillars feed mainly on oak leaves, but also of poplar (Populus ), birch (Betula ), maple (Acer), hornbeam (Carpinus ), beech (Fagus ), willow ( Salix), stinging nettle (Urtica ), blueberries (Vaccinium ) and other plants. You need three to four weeks before they pupate wrapped in a sheet. After another three to four weeks to slip the finished butterfly.
Flight times and caterpillars
The night - and night-active moths fly in one generation in the upper portions of the tree crowns. But they are also found in the day. Their development can be extended in cold regions to two years, but in warm areas, they also fly in two generations. The moths have a life expectancy of only 5 to 10 days.
Harmful effect
The oak leaf is a dreaded forest pest. In Europe, for example in the great oak stands of Westphalia and the Rhineland, it always comes back to outbreaks that lead to bald seizure of large parts of the food plants. This often occurs in the lowlands, in loose forests or individual, free-standing trees. The trees are weakened and can thereby greatly by additional factors such as Dryness die. In addition, the renewable leaves often of oak mildew ( Microsphaera alphitoides ) are affected. But healthy oaks may even outlast a multi-year infestation. Some areas are crowned each year varies heavily infested, others only occasionally.