How to treat cottony cushion scales on yard trees?

How to treat cottony cushion scales on yard trees?

Controlling cottony cushion scales on yard trees requires a combination of winter sanitation and spring control.

Winter and early spring (dormant season) control

This is the critical prevention period — the most work but the most effective:

1. Scrape old bark — use a scraper or wire brush to remove loose, cracked bark on trunks where scales overwinter.
2. Remove egg sacs — find white, cottony egg sacs on trunks, scrape them off, and burn them or drop them into boiling water.
3. Clean the ground — remove all fallen leaves, weeds, and pruned branches from under the tree.
4. Whitewash trunks — apply limewash to the lower trunk (lime:water:salt ≈ 1:5:0.1) to protect against both pests and frost.
5. Sticky barrier bands — wrap sticky insect tape around the trunk 30-50 cm above ground to prevent nymphs from climbing up.

Spring nymph emergence (critical control period)

• When nymphs begin hatching and moving in March-April, spray dinotefuran-containing household insecticide on trunks and main branches.
• Focus on bark crevices and branch crotches.
• For tall trees, concentrate on the inner canopy and lower branches.
• Spray every 10-14 days, 2-3 times consecutively.

Growing season management

• When a few insects are found, wipe them off with a damp cloth or brush.
• Prune dense branches to improve light and air circulation.
• Spray dinotefuran-containing insecticide on the ground under trees to prevent fallen nymphs from climbing back up.

Precautions

• If trees are very tall and household sprayers cannot reach, hire a professional tree care company.
• Wear gloves and a mask when spraying.