In April, the winter egg hatches. The nymphs take to the leaves and lay eggs, all female, each of which lays eggs again (as many as seven cycles). They produce galls on the leaves, in which they continue to live and deposit their eggs. Some migrate to the roots, where their juices, which they inject, are toxic.

From egg to adult form, they go through several stages.

From the last clutch, late summer, winged and wingless forms emerge, laying male and female eggs (September). The female and male nymphs mate and the winter egg is laid under the bark of the plant around October.

 

Below four photos. 1: phylloxera adult form and eggs at roots. 2. Winged form. 3. Galls on leaf. 4. exposed gall with adult form and eggs.