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Leyland Cypress in Mojave: Bore Mites, Ants & Sap

Palmdale, CA: Leyland cypress with bore mites (treated with Cygon spring/fall), 16-16-16 fertilizer every 6 weeks. Suddenly ants everywhere, sap oozing from bark. Losing battle.

The expert said 16-16-16 is too high N-P-K; use lower (3-2-1) evergreen fertilizer like Holly-tone, spring and fall. Check for fungal rust/canker on foliage—prune only in dry weather. Ants may indicate carpenter ants in borer-damaged wood. Dormant oil spray in early spring smothers eggs. Consult local extension or licensed arborist for restricted pesticides.

Corrected Care

Fertilizer: low N-P-K (Holly-tone), 2×/year.
Prune dry only to limit canker spread.
Ants: check for carpenter ants in dead wood.
Local expert for legal, effective pesticides.

Conifers: Diagnosing and Treating Browning Fraser Firs and Cedar Trees; Lichens on Trees: Harmless Indicators of Stress, Not Killers; Magnolia Stress in Galveston: Semi-Evergreen Leaf Drop, High-P Fertilizer for Blooms; Robins in Garden: Netting Berries, Feeding Seed Elsewhere; Dealing with Neighbor's Cypress Trees Damaging Pool and Fence; Assessing Survival of Transplanted Trees and Shrubs After One Year; Phototropic Lean in Green Giant Arborvitae: Staking Limitations; Cypress Trees Damaged by Vine Removal: Pruning Dead Wood and Fertilizing for Recovery; Date, Fig & Coconut Trees: All Palms?; Diagnosing Interior Dieback in Leyland Cypress Hedge

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