Young stages of Hydrangea scale are light brown and flat. Adult stages are round and more swollen. From June and July remarkable white egg sacs become visible. There is only one generation per year in which a single female can produce up to 1000 new scales. Depending on the season, young stages can be found on the leaf, petiole or branch. Adult stages are usually found on the underside of the leaves.

Hydrangea scale damage

Damage by the Hydrangea scale ismainly cosmetic. During heavy infestations, large amounts of honeydew are produced. The honeydew acts as a growth medium for black sooty mold fungus which will turn the leaves black. Thiscan hamper photosynthesis.