Mexican Orange bushes problem

Question: Hello our beautiful Mexican Orange shrubs seem to have something going on. There is white powdery covering to some of the leaves. Any advice?

responder: Jacki D., Master Gardener Diagnostician Volunteer (Washington, Multnomah and Clackamas Counties) Oregon State University Extension Service Volunteer Metro Master Gardeners (http://metromastergardeners.org/) Replied April 28, 2023, 3:43 PM EDT
response: Oh, there is something happening to your Choisya ternata, Mexican orange blossom, plants. It could be environmental conditions, pests, or disease. The photo just doesn’t give enough information. Provide more photos to help with diagnosis. One at a distance showing the plant and surrounding landscape. Another close of one leaf, and one of a leaf underside. If the lighting is right, your camera should provide a clear, in-focus snapshot even up close. Next, describe what you see. Anything looking like bugs on leaf undersides? Does the white seem to be powdery? Does it rub off? Are leaves sticky? What about the pattern of damage? Is it consistent over the whole plant, or only on one part, like the lower portion, or part in the most sun. What treatments does it get, for instance fertilizer? What about nearby areas, such as weed treatments on lawn next to it. Finally, share a bit about when you first saw this damage, how your water in summers. What about pruning? How long have you grown these plants in this location? Has anything changed, like a big tree removed, or drainage lines dug near the plant?

responder: The Question Asker Replied April 28, 2023, 5:20 PM EDT
response: Thank you! I will send separately photos of the plants in the landscape, a close up of underside of leaves and the top side. There’s plants have been in this spot 4-5 years. The problem is starting with the plant on the right side of the row (gets more shade there). The white stuff doesn’t rub away, the plants are not sticky. Nothing has changed near the plants -and we have a sprinkler system that waters them (not a drip). Didn’t prune them last year but did the year before. Sent from my iPhone On Apr 28, 2023, at 12:43 PM, Ask Extension <<personal data hidden>> wrote:﻿

responder: Jacki D., Master Gardener Diagnostician Volunteer (Washington, Multnomah and Clackamas Counties) Oregon State University Extension Service Volunteer Metro Master Gardeners (http://metromastergardeners.org/) Replied April 28, 2023, 6:10 PM EDT
response: The underside photo isn't in focus enough to determine if anything is there. Try again? Do you see bugs or anything on the underside? When did you first notice the damage?

responder: The Question Asker Replied April 28, 2023, 7:55 PM EDT
response: Hope this is better. I don’t see any bugs. We first noticed this problem several weeks ago but it is very possible it was there longer. Sent from my iPhone On Apr 28, 2023, at 3:10 PM, Ask Extension <<personal data hidden>> wrote:﻿

responder: The Question Asker Replied April 28, 2023, 8:14 PM EDT
response: Here is a better photo not much to see on the underside. No bugs that I can see. Thank you, Linda 



Sent from my iPad

responder: Jacki D., Master Gardener Diagnostician Volunteer (Washington, Multnomah and Clackamas Counties) Oregon State University Extension Service Volunteer Metro Master Gardeners (http://metromastergardeners.org/) Replied April 28, 2023, 8:26 PM EDT
response: The photos are too low of resolution to allow zooming in to see full details. I wish we could make site visits to see your plants. My suggestions are to take a branch in plastic to a quality area nursery with a help desk, or contact Metro Master Gardener Volunteers directly. You can email higher resolution photos and maybe successfully long-distance diagnose the plants.