''Trioza alacris'' is a sap-sucking

hemiptera Hemiptera (; ) is an order (biology), order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, Reduviidae, assassin bugs, Cimex, bed bugs, and shield bugs. ...

n bug in the family ''

Triozidae Triozidae is one of seven families collectively referred to as jumping plant lice. They have traditionally been considered part of a single family, Psyllidae, but recent classifications divide the group into a total of seven families; most of th ...

'' which creates

gall Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants, fungi, or animals. Plant galls are abnormal outgrowths of plant tissues, similar to be ...

s on the leaves of ''

Laurus ''Laurus'' () is a genus of evergreen trees or shrubs belonging to the laurel family, Lauraceae. The genus contains three or more species, including the bay laurel or sweet bay, ''L. nobilis'', widely cultivated as an ornamental plant and a cul ...

'' species. It is found in Europe.

Description of the gall

''Trioza alacris'' causes the edges of leaves to thicken and roll downwards forming pale, elongated pouches. The galls can house two generations in a summer, of up to thirty pale-green nymphs, which are covered in a white wax. Adults can also be found in the gall. The adults usually overwinter in leaf litter but can also spend the winter in the gall. Species of ''Laurus'' galled include the Azores laurel (''

Laurus azorica ''Laurus azorica'', the Azores laurel or Macaronesian laurel, is a small, evergreen tree in the laurel family (Lauraceae), found only on the Azores island group in the North Atlantic. Description The Azores laurel is a small dioecious tree, grow ...

''), bay tree (''

Laurus nobilis ''Laurus nobilis'' is an aromatic evergreen tree or large shrub with green, glabrous (smooth) leaves. It is in the flowering plant family Lauraceae. It is native to the Mediterranean region and is used as bay leaf for seasoning in cooking. I ...

''), ''

Laurus novocanariensis ''Laurus novocanariensis'' is a large shrub or tree with aromatic, shiny dark-green foliage. belonging to the evergreen tree genus ''Laurus'' of the laurel family, Lauraceae. The genus includes three species, whose diagnostic key characters ofte ...

'' and ''

Persea indica ''Persea indica'' is a large, evergreen tree in the laurel family (Lauraceae), native to humid uplands on Madeira and the Canary Islands in the North Atlantic. It belongs to the genus ''Persea'', a group of evergreen trees including the avocado. ...

''.

References

Triozidae Hemiptera of Europe Gall-inducing insects Insects described in 1861 {{Sternorrhyncha-stub