Boxwood psyllid, Psylla buxi, can be found feeding on American boxwood in many portions of Illinois. American boxwood is very susceptible to attack, whereas English boxwood is less severely attacked.

Boxwood psyllids, often referred to as jumping plant lice, are small (1/16-inch), grayish green insects that are normally covered with a white, waxy, filamentous secretion that partially covers the body, providing protection from parasitoids and sprays of pest-control materials. Winged adults appear in late May and June. They can be seen flying around plants. Adults may bite humans; however, the bites are not serious. Females insert, between or under bud scales, spindle-shaped, orange eggs during early summer. Boxwood psyllid overwinters as an egg.

Eggs hatch into yellowish nymphs that begin feeding as soon as buds begin to open in early spring. The first-instar nymphs feed by sucking plant fluids from terminal leaves as they unfold and expand in spring. Their feeding causes leaves to yellow, curl, and form a cup, which conceals and protects the nymphs. There is one generation per year.

The pest-control materials acephate (Orthene), carbaryl (Sevin), insecticidal soap, and horticultural oil can be used for control. Particularly with insecticidal soap and horticultural oil, coverage within the cupped leaves is essential to be sure that the nymphs are directly contacted with the insecticide. Acephate and carbaryl are effective on the adult stages of box wood psyllid.