Identifying and Controlling Pests on Ponderosa Pine

A large ponderosa pine near Denver developed thousands of tiny grey-white "spiders" and sticky residue after being sprayed with Astro for pine beetle prevention. The tree appears healthy with no needle yellowing or drop.

Diagnosis: Likely Aphids, Not Spider Mites

The visible size, lack of webbing, and sticky honeydew point to aphids, not spider mites. Astro likely eliminated beneficial predators, allowing aphid populations to explode.

Treatment Options

• Bayer Advanced Tree & Shrub Insect Control (soil drench): Systemic treatment absorbed by roots, killing aphids as they feed. Long-lasting but takes weeks to reach foliage.
• Ortho Systemic Insect Killer (foliar spray): Faster action but requires thorough coverage of large trees.

Confirm identification with a magnifying glass—aphids have 6 legs, spiders have 8. For tall trees, professional application may be needed.