Its telltale trait, though, is its feeding pattern. As seen in the image above, the elm zigzag sawfly is known to eat the leaves of an elm tree in a zigzag path.

Updated: Sep 16, 2023 / 12:02 PM EDT DELAWARE, Ohio (WCMH) – An invasive insect known for leaving unique patterns on the leaves of elm trees has been spreading this summer.

The elm zigzag sawfly eats a distinctive pattern into leaves that can be damaging and deadly to the elm tree. (Photo: Kelly Oten/NC State).

Updated: Sep 16, 2023 / 06:02 AM HST DELAWARE, Ohio (WCMH) – An invasive insect known for leaving unique patterns on the leaves of elm trees has been spreading this summer.

Updated: Sep 16, 2023 / 12:01 PM EDT DELAWARE, Ohio (WCMH) – An invasive insect known for leaving unique patterns on the leaves of elm trees has been spreading this summer.