Pecan Phylloxera: Brown Leaf Blisters Caused by Gall-Forming Insects

Identifying Pecan Phylloxera

Small brown blisters (galls) on pecan leaves are caused by phylloxera, tiny aphid-like insects. They inject saliva that induces gall formation, then live protected inside.

Life Cycle and Timing

Phylloxera overwinter as eggs on bark. In early spring, as buds break, nymphs emerge and move to new leaves to form galls. Once inside galls, they're shielded from sprays.

Control Window: Early Spring Only

Effective treatment must occur at bud break, before galls form. Dormant oil or insecticides applied at this narrow window can reduce populations. Summer sprays are ineffective.

Impact and Reality Check

• Heavy infestations make trees unsightly but rarely kill them.
• Nut production may be reduced if galls form on nutlets.
• Natural enemies often suppress populations over time.

Resource

Detailed phylloxera information: TreeHelp.com