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Pemphigus spyrothecae

Poplar spiral gall aphid

Description

On leaf stems is formed a spiral gall in which develop aphid larvae. Eggs laid in au­tumn by fertilized females of the generation sexuales are a wintering developmental stage. Females lay one large thick-walled egg only especially into slits of the stem and branch bark of host trees. At the beginning of flushing of poplar leaf buds (usually in mid-April), fundatrices representing individuals of the first generation emerge from the eggs. Larvae of the instar move to the most burst buds where they begin sucking. Through salivary secretions discharged into incisions during sucking, the petioles bend first and soon twist right (seldom left). In the cavity of a spiral gall, the fundatrix matures. The aphid does not move in to other plant species as some of its related species do. The galls are more visible in the second half of summer. In Europe it is considered to be an abundant species that often shows mass outbreaks and sometimes is harmful.

Symptom

On leaf stems is formed a spiral gall in which develop aphid larvae.

Tree Species: Poplar

Part of a plant- attacked: Leaf / Needle

Pest significance: Less harmful

Pest Category: Insects

Invasive Species: No

Present in EU: Yes

Seasonal frequency of occurrence

Seasonal frequency of occurrence