Euonymus leaf-notcher invasion … second year. - Ask Extension
I’m in north-east Baltimore city. Spring 2023 two euonymus tall trees plus one shrub were invaded by leaf-notcher caterpillars. I was not able to re...
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Euonymus leaf-notcher invasion … second year. #865871
Asked April 25, 2024, 12:25 PM EDT
I’m in north-east Baltimore city. Spring 2023 two euonymus tall trees plus one shrub were invaded by leaf-notcher caterpillars. I was not able to remove eggs or afford professional help so, unfortunately the critters came back. There are many similar trees & shrubs in my neighborhood…two yards away are several 14 foot tall trees and they are not yet affected. I had my backyard 16 foot tall, broad canopy tree cut down and removed two side trunks from other tree near the front of the house. The remaining tree and the shrub are virtually denuded of leaf. I don’t know if I should maintain these infected plants - they may recover over the summer but I think next year will be the same and I worry for my neighborhood. Any thoughts?
I’m writing also to alert you that these invaders have arrived this far north. Thank you for any suggestions. (I am on a limited income, have been taking care of my own property for over two decades but can no longer climb ladders to prune or protect as I used to do.)
PS: I could send photos but have to ask for family help - I don’t know how to attach them.
Baltimore City County Maryland
Expert Response
Our Euonymus Leaf Notcher web page needs revision, but we have seen them in Maryland for some time now, including in your area. To our knowledge, they only consume Euonymus and its relative Bittersweet vine (most growing in Maryland is the invasive Asian species), so do not threaten other unrelated landscape perennials, trees, or shrubs. Evergreen Euonymus plants are over-planted and not native in Maryland (and one species is actually invasive, spreading into woodlands), but they are vigorous enough that they can usually withstand defoliation by these insects and recover just fine, even if it occurs annually. If a Euonymus does not recuperate after a caterpillar outbreak, odds are some other overlapping factor was causing the plant too much stress.
Since there is little you can do for this insect other than manual removal or resorting to lower-toxicity pesticide sprays (not something we'd generally recommend for caterpillars not causing long-term damage), the solution might be to replace the plants with other species of shrubs. We realize this can be an undertaking of expense and labor, but perhaps there is a landscaping company you can hire to help that has affordable rates. If you do prefer to keep and treat the plants, it would be simplest to drastically cut them back to within about a foot or so of the ground to force regrowth, which will not only remove the majority of the current caterpillar population, but it will also make new foliage much easier to treat with B.t. (a naturally-derived caterpillar pesticide) if you decide to use it. Once the caterpillars are too old or mostly done feeding, though, it won't be effective.
Miri
Since there is little you can do for this insect other than manual removal or resorting to lower-toxicity pesticide sprays (not something we'd generally recommend for caterpillars not causing long-term damage), the solution might be to replace the plants with other species of shrubs. We realize this can be an undertaking of expense and labor, but perhaps there is a landscaping company you can hire to help that has affordable rates. If you do prefer to keep and treat the plants, it would be simplest to drastically cut them back to within about a foot or so of the ground to force regrowth, which will not only remove the majority of the current caterpillar population, but it will also make new foliage much easier to treat with B.t. (a naturally-derived caterpillar pesticide) if you decide to use it. Once the caterpillars are too old or mostly done feeding, though, it won't be effective.
Miri
Thank you very much for your reply. I did take photos but based on your info..I don’t think posting them is necessary. (I’ll save them temporarily just in case they might be useful.) The large back tree is cut down to six foot ‘cane-like’ trunks and should sprout new growth. The side tree will recover over the summer…the caterpillar population is minimizing and may soon finish. Fingers-crossed other shrubs are safe.
Your response was comforting - I better understand the problem, my options and that it’s not the end of the world for me or my neighborhood! I’m so glad you all exist…once more ‘Thank You’ very, very much!
Glad to be of help, and you're welcome!
