It sounds like you are dealing with a similar insect pest, the iris borer. They are a common iris pest and their life cycle is much like the squash vine borer: an adult moth lays eggs on or nearby iris foliage, then these eggs eventually hatch and the larvae tunnel down through the leaves to feed on the iris rhizomes. The eggs are laid in late summer and overwinter until late spring, when they hatch. Therefore, late spring and early summer are the times to look out for these pests and to take action against them.
One thing you can do is to always clean up around your iris bed in the fall. Remove any dying plants, dead leaves, or other debris that borer eggs could overwinter on. This won’t prevent borer issues outright, but will help. In the late spring, look for signs of tiny, 1/4-inch larvae boring through the iris leaves. If you spot them, you can easily squish them with your fingers. Additionally, look into organic products that contain parasitic nematodes (Heterohabditis, Steinernema), which will infect and kill the larvae but won’t be bad for beneficial bugs.
Hi Debbie,
It sounds like you are dealing with a similar insect pest, the iris borer. They are a common iris pest and their life cycle is much like the squash vine borer: an adult moth lays eggs on or nearby iris foliage, then these eggs eventually hatch and the larvae tunnel down through the leaves to feed on the iris rhizomes. The eggs are laid in late summer and overwinter until late spring, when they hatch. Therefore, late spring and early summer are the times to look out for these pests and to take action against them.
One thing you can do is to always clean up around your iris bed in the fall. Remove any dying plants, dead leaves, or other debris that borer eggs could overwinter on. This won’t prevent borer issues outright, but will help. In the late spring, look for signs of tiny, 1/4-inch larvae boring through the iris leaves. If you spot them, you can easily squish them with your fingers. Additionally, look into organic products that contain parasitic nematodes (Heterohabditis, Steinernema), which will infect and kill the larvae but won’t be bad for beneficial bugs.