Which stage of Euonymus scale causes plant damage?

Which stage of Euonymus scale causes plant damage?

• A. Females and crawlers feeding under scale covers
• B. Males on upper leaf surface
• C. Eggs inside bark
• D. Pupae on roots

Answer: (A)

The key idea is that plant damage from scale insects happens during feeding. For Euonymus scale, the main damage comes from sap sucking by the adult females, who remain attached under their protective covers, and by the mobile crawlers as they settle and start feeding. Eggs inside bark don’t feed the plant, and pupae on roots aren’t the feeding stage for this pest. So the stage that causes the damage is the feeding of females under their covers and the feeding of crawlers.

The key idea is that plant damage from scale insects happens during feeding. For Euonymus scale, the main damage comes from sap sucking by the adult females, who remain attached under their protective covers, and by the mobile crawlers as they settle and start feeding. Eggs inside bark don’t feed the plant, and pupae on roots aren’t the feeding stage for this pest. So the stage that causes the damage is the feeding of females under their covers and the feeding of crawlers.