Species (Lymantria dispar) of tussock moth, a serious pest of trees. The European strain was introduced into eastern North America c. 1869. The heavy-bodied, weak-flying female is white with black zigzag markings and a wingspan of 1.5–2 in. (38–50 mm). The smaller, darker male is a stronger flier. The voracious larvae can completely defoliate deciduous trees within weeks. The larger Asian gypsy moth (wingspan of about 3.5 in., or 90 mm) is even more threatening because the female is a stronger flier, enabling it to spread quickly, and the larvae eat the leaves of both conifers and deciduous trees. It was introduced into northwestern North America in 1991. Sprayed insecticides remain the most effective means of control.