Now is the period to check Boxwoods for the presence of mites and psyllids. Immature mites are yellow-tan in color with many legs. They feed on the leaves causing them to yellow, turn brown and drop off prematurely. The psyllid nymphs are green and flattened with fluffy white wax on their posterior. Their feeding causes the margins of leaves to cup and become stunted. The use of horticultural oil and insecticidal soap will help to control light infestations of these pests.