Leaf roll galls on leaves of the bay laurel, Laurus nobilis. The picture shows galls of differing ages at the edge of two bay leaves. The rolling is caused by the psyllid bug Lauritrioza alacris (formerly Trioza alacris). The insects lays eggs between cells on the epidermis of the leaf; they hatch to nymphs. As it feeds, the nymph causes the leaf edge to roll downwards. After only a few days, the nymph is enclosed within a rolled tube of at least two turns. As the nymph matures, the tube loosens to allow its escape. The gall to the right is empty; the brown area is the site of the insect's exit. The life cycle lasts only a few weeks, and several generations can occur over one summer season. L. alacris was imported into the UK on commercial bay trees, and is common in gardens in southern districts; it is slowly extending it range northwards | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Burgess, Dr. Jeremy |
Taille de l’image : | 3468 px × 5212 px |
Model Release : | Non requis |
Restrictions : | - |