Lacebug and thrips are two insects that leave droppings on the undersurface of the leaves where they feed. The white blotches or stippling injury is also typical, shown here on aster. The adult lacebugs, usually found on the leaf undersurface, are easily recognized by the lacy brown-and-white patterning of their wings. Rarely a greenhouse pest, some lacebugs are common pests on andromeda, azalea, cotoneaster and sycamore.