Diagnosing Sticky Residue on Raywood Ash Trees

A 20+ year old Raywood Ash in Vacaville, CA drops tacky white powder onto surfaces below. No obvious insects visible, but some leaves show white soft specks underneath—likely cottony scales or aphids producing honeydew that hosts sooty mold.

Recommended Treatment

Bayer Advanced Tree & Shrub Insect Control applied as a soil drench. Roots absorb the systemic insecticide, transporting it to leaves where feeding insects are killed. Takes 2-3 weeks to reach foliage but lasts all season.

For large trees, foliar spraying is impractical. The "Protect & Feed" variant contains fertilizer and works similarly but is pricier. Available at Home Depot, Lowe's, and Orchard Supply Hardware.