Maryland Pesticide Applicator Category 3: Ornamental and Turf Practice Test

White stippling on leaf tops from azalea lace bugs happens because these pests feed by piercing the leaf surface and sucking out small amounts of sap from the leaf cells. This sap removal kills or distorts the upper epidermal cells, creating the characteristic white specks you see on the upper leaf surface. Both nymphs and adults contribute to this feeding, so the stippling is tied to piercing-sucking injury, not chewing.

Chewing insect damage would leave holes and irregular chewing, not fine stippling. A fungal infection would typically cause spots or moldy patches, not the uniform speckling. Nutrient deficiencies usually cause general yellowing or interveinal chlorosis rather than pinpoint stipples.