Pest on our hedge

Asked March 24, 2017, 12:22 AM EDT

I think we have a laurel hedge and is got an infestation of tiny white bugs on the leaves and branches. The hedge is dying and we'd like to try to save it. I do keep bees so I don't want to spray a toxic chemical on the hedue, is there anything we can do?

Multnomah County Oregon

3 Responses

Thanks for giving Ask an Expert a chance to help you with your laurel hedge.

The photo appears to show a scale insect (perhaps cottony camellia scale) or a mealybug. Both can appear fuzzy and will take up residence on leaves, twigs, and branches. Feeding by a large infestation can cause the plant to loose vigor and drop leaves. Here is a photo of the cottony camellia scale.

For a positive identification, you can bring a sample to the Multnomah County Master Gardener office in Montgomery Park, 2701 NW Vaughn St., Suite 450, Portland. 10AM - 2PM Monday – Friday or call and talk to them at 503-445-4608.

If you can take a more close up photo, that would help, too. You can upload them to Ask an Expert or to the Master Gardeners at mcmastergardeners@yahoo.com.

Regards,

I stopped by today to get some help but first it looks like you need more photos to identify the hedge. Here are more photos of the hedge and I left an infected leaf at the office with Winnie.

Thanks so much for any help you can give me!

Kristina

Well, these are great photos, and it looks like your hedge is not a laurel but a Japanese or evergreen euonymus (Euonymus japonicus). Here is a photo from the Oregon State University plant database, for comparison, and a description.

With this in mind, along with your previous photos, I would say that your hedge is infested with euonymus scale. Here is a photo of the insect on leaves and branches. From the looks of the hedge, it appears that they have done significant damage. The evergreen euonymus is also susceptible to powdery mildew, which can also reduce its vigor.

An evergreen euonymus hedge can often take hard pruning and be revitalized. However, the lower parts of your hedge don’t appear to have many leaves left to feed the plant. This might need a visit by a certified arborist for on-the-spot advice.

Here’s what you could try. After spring flowering, cut the hedge back to about half its height or fence height. This will eliminate many of the scale insects. Spray the remaining branches, and insects, with a horticultural oil to smother them. Plan to spray again in early summer, because a second generation is likely.

As spring progresses, leaves should emerge. Water the hedge, as weather dictates, because drought-stressed plants are more likely to attract these pests. Too much fertilizer also makes the hedge more susceptible to the euonymus scale, but a spring fertilizer application should help the new growth get going.

Good luck getting that hedge back in shape for the coming years.

Regards,