What is eating my green bean seedling? The leaves look like lace.

June 14, 2022 Ask the Expert, Managing Insect, Diseases, and Animal Pests

Question:

My 4-inch green bean seedling leaves are being eaten. The leaves look like lace! I can’t find the culprit but the crop is being destroyed. Any ideas what this could be?

Answer:

Lynne M. Holland, Horticulture and Social Media Professional

Without a photo it is really just a guess. You have to know what you have before you can deal with it.

This time of year the things that will eat the leaves of a bean plant are primarily in the slug or snail family. This damage looks like something has eaten the leaves and left swiss cheese like holes in the leaves. This resource on slugs and snails has good general information (click on the blue underlined test to go to the fact sheet). The best way to know if this what you have is to go into the garden after dark and shine a flashlight on the underside of the leaves. They don’t move too fast so if you have them you will see them.

If it were later in the summer I would wonder if it was a Mexican Bean Beatle as they really make the leaves lace like but they don’t show up until July here in Maine. Here is a good general resource on pests on beans. There are quite a few to deal with so take the time to really look at the leaves for signs of who is eating them. Any eggs, shells or webs? Do you see their frazz (bug poop) or small insects where the leaves meet the stem or where new growth is starting. All of those are clues to help you identify the pest and from there you will know what you are dealing with.