What's eating my arizona cypress?

Arizona Cypress is drought-adapted and ordinarily low-maintenance, but cypress bark beetles (Phloeosinus spp.) are a documented serious threat on water-stressed trees. Bagworm and scale insects are additional concerns in garden settings. Cypress canker can affect weakened specimens. Good moisture management is the key preventive.

Boring into bark of drought- or heat-stressed trees; pitch tubes and frass at entry holes; larval galleries disrupt vascular tissue; can kill trees quickly. Maintain adequate irrigation — healthy trees resist attack; apply preventive pyrethroid trunk sprays before beetle flight season; remove and destroy infested wood.

Silken bags of foliage hanging on branches; larvae strip needles causing dead brown patches and branch death in severe attacks. Manually remove bags in winter; apply Bt to young larvae; use permethrin or spinosad for larger caterpillars in late spring.

Armoured scales on stems weaken the tree; sticky honeydew deposits attract sooty mould; heavy infestations cause yellowing and dieback. Apply horticultural oil at crawler emergence; systemic drench for persistent infestations; prune and destroy badly affected stems.

Canker lesions on branches; resin exudation; branch dieback especially under drought or heat stress. Prune below the canker with sterilised tools; improve irrigation; avoid planting in exposed, desiccating conditions.