20-Year-Old Althea Tree Dying: Whiteflies or Rain-Driven Disease?

Texas. 20-yr-old althea (12+ ft) suddenly dying bottom-up. Was blooming. Whiteflies on nearby plants. Heavy rain month. High yard spot. Save it?

Likely Whitefly + Rain Diseases

Whiteflies suck sap → weakening, sooty mold.
Leaf spot / rust thrive in constant rain (brown/black spots or orange pustules).

Large, old plants can recover if treated promptly.

Shrubs: Mandarin Tree: Sooty Mold and Insect Complex in Australia; White Birch Decline After Spring Pruning: Sap Flow and Bacterial Wetwood; Whitefly Invasion on Hibiscus: Neem Oil, Patience, and Cold Hope; White Ash Tree Decline After Bark Damage: No Cure, Monitor for Borers; Diagnosing Pine Tree Decline in Southern Illinois; Pine Tree Roots Cut for Pool: Is It Dying?; Saving a Poorly Planted Evergreen in Minnesota; Transplant Shock in Young White Pine: Will It Recover?; Japanese Black Pine Near Ocean: Fertilize, Stop Annual Injections; Controlling Whiteflies on Tall Orchid Trees: Systemic Insecticide Considerations

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