Treating Scale Insects on Plants Naturally

Overview

Scale outbreaks often follow garden stress: over/underwatering, excess nitrogen, or pesticides that kill beneficial predators. Though tiny (1/12–1/5 inch), scales coat plants in cottony white or colored bumps. Rose leaves darken and wilt; other plants yellow and drop leaves. Waxy scales can be scraped off with a dull knife; early infestations respond to rubbing alcohol on a cotton swab. Attracting predator insects is a sustainable, eco-friendly control.

Attracting Beneficial Insects

Step 1: Green Lacewings

Larvae voraciously eat scale. Buy eggs/larvae commercially; ~5,000 larvae cover 2,500 sq ft. Plant yarrow, oleander, Queen Anne's lace, or wild lettuce for nectar to retain adults.

Step 2: Ladybugs

Adults and larvae devour scale, aphids, whiteflies, spider mites. Plant alfalfa, goldenrod, morning glory, coffeeberry, angelica, yarrow, oleander, or ragweed (if no allergies) to support populations.

Step 3: Braconid Wasps

Purchase eggs for humid areas >59°F. Wasps parasitize host insects. Plant fennel to retain them; they also like daisy, strawberry, white clover.