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Hackberry Tree Decline: Aphids, Weed Barrier, and Root Damage

A large hackberry near a patio drops blackened leaves. Owner installed weed barrier, rocks, potted plants, and hung ferns; clipped some roots. Ants and black sooty mold are everywhere.

Primary Issue: Aphids → Sooty Mold

Black coating is sooty mold on aphid honeydew. Ants farm aphids for honeydew. Control aphids → mold and ants disappear.

Secondary Stresses

Weed barrier raised soil temperature → root stress.
Root clipping and digging added stress.
Combined stress triggered early leaf drop.

Action Plan

Treat aphids with systemic imidacloprid soil drench (Bayer Advanced Tree & Shrub).
Water deeply to offset root disturbance.
Leave weed barrier in place; tree will acclimate if kept watered.

Do not spray foliage on large tree; soil systemic is effective and safer for beneficials.

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