San Jose Scale on Crabapple: Ants Farming Honeydew

Question: Black ants on 2-year-old crabapple with bumpy bark and new growth. Are ants protecting or eating the bumps? How to remove?

Answer: San Jose Scale (Quadraspidiotus perniciosus)

Grey, 0.1-inch covers on bark; feed on sap via thread-like mouthparts. 4 generations/year in South. Females produce 400 crawlers over 6 weeks.

Dormant oil spray (early spring, before bud break) – smothers overwintering scales
In-season sprays target crawlers (timing critical)
Systemic: Imidacloprid (Bayer Advanced Garden Tree & Shrub) – soil drench; tree absorbs, kills feeding scales

Bypasses spray timing/c coverage issues. Professional product = Merit (same active).

Pests: Ming Tree (Polyscias) Sticky Leaves: Scale Insects; Crabapple Sparse Blooms and Bark Craters: Atomic Grow for Insect Cleanup and Vigor; Black Scaly Substance on Willow: Soft Scale Infestation; Cottony Aphids on Young Sargent Crabapple: Identification and Control; Lumpy Growths on Crabapple: Black Knot or Cedar-Quince Rust; Scale on Massive Indoor Fig Tree: Hand-Clean or Systemic (If Commercial); Cottony Scale on Mimosa: Identification and Systemic Control; Scale Insects on Ficus Tree: Identification and Treatment; Roundup on Crabapple Suckers: Tree May Die; Crabapple Tree Guide: Varieties, Planting, Pruning, and Disease Care

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