About Podosesia syringae (Harris, 1839)
Podosesia syringae, commonly called the ash borer or lilac borer, is a clearwing moth that belongs to the family Sesiidae. It is distributed across all of North America, and it is known to act as a pest on ash and lilac plants. Adult ash borers feed on nectar. They lay their eggs in the bark of lilac, ash, and privet, and they may also attack closely related plant species within their North American range. Larvae feed beneath the bark, chewing into the sapwood of their host plants. This larval feeding can destroy a tree's phloem, weakening and potentially killing already stressed or very young trees by increasing their risk of wind damage or wilting. Pupae overwinter inside the feeding galleries created by larvae, and emerge as adult moths the following spring. Adults begin emerging between April and July. This emergence corresponds to 300 to 500 growing degree days above 50 °F (10 °C), or approximately one week after lilacs finish their full bloom.
