They are a type of insect known as sawflies. Two generations of pear slug occur. When severe defoliation is threatened, pear slug injury should be controlled. Pear slug larva on leaf and characteristic feeding injury. Among the more heavily damaged plants in Colorado are cherry, cotoneaster, plum, apricot, pear, hawthorn and mountain ash.
Pear slugs are dark green to orange, swollen at the head end, and slimy.
They tend to lighten in color as they grow older. Pear slugs can be confused with common Garden slugs, but they are really Insects. History and Damage Pear slugs pass the winter underground in the pupal stage. During late spring, the adult Insects emerge to mate and lay eggs. They lay eggs in slits made in the leaf.