Leaf Roller Worm

Asked April 4, 2020, 11:06 PM EDT

I think I have identified the nest in my Japanese Hollies as a leaf roller. I asked a question last week and I couldn't locate the worm that the expert told me about, but I found a worm and it is 1/2 inch long, light green with a brown head. That one was identified as a leaf roller as far as I could determine. I am going to spray with Spinosyn A and Spinosaid D. Not sure of the spelling. I have cut out the badly infested branches and will spray when it is warm next week. I guess my question is, how can I prevent this infestation next spring? Can I spray with dormant oil next November, like apple trees.? I know they are not native and if it will always be a problem, could you suggest another plant that is native or at least heartier, not susceptable to diseases or insects. A narrow screening plant that will fit into a narrow space along a fence? Linda K.

Washington County Oregon

1 Response

Spinosid impacts insects that eat or touch it. Since the leaf rollers are curled inside of leaves, the insecticide might not work very well to kill them.

Beyond pruning and hand picking insects, there is not much you can do to prevent the problem short of using systemic insecticides like imidacloprid. These systemic products also make their way to the flowers, which impacts pollinators.

How important are the Japanese Holly plants to you?

Some suitable replacements include Oregon grape and evergreen huckleberry. Both are native and not susceptible to common pest problems.

Good luck.