The past couple weeks, several customers have brought in pieces of Ruellia (Mexican Petunia) with worrisome white splotches on the leaves. At first glance, it could appear to be a fungal issue or even a chemical or paint residue, but that’s not it… Here’s what to look for and our recommendation for treatment.
The white funk is actually a type of growth distortion called erineum caused by tiny mites called eriophyid mites (Acalitus ruelliae). So that means fungicides would be a waste of time and money to solve this issue. We recommend treating organically with All-Seasons Oil Spray (a horticultural oil). Repeat the treatment every 5 to 7 days for a total of 3 treatments, wait until Spring, then cut the plants down to ground level. This should kill the mites and the plants should grow back out and look beautiful again. Another approach would be to use organic Spinosad soap or Bee Safe 3-in-1 Spray to treat the mites, then cut to ground level in Spring and wait for clean regrowth.
-DeAnna
Dianna Bluntzer Sherman says
Our mesquite tree leaves are covered with something that looks like this. Is it the same mite?
DeAnna says
No. You have powdery mildew. Do not worry. Let them drop their leaves for winter
Andrew F says
It also helps to have the area cleared of debris, get good air flow and remove the excess mulch and dead old growth from the base of the plant. I agree its powdery mildew. Getting to wet, plant is a jumbled mess with no active pruning causing a jumble of growth to trap moisture and produce the unsightly mildew.
Ruth Ann Moran says
Is there a home remedy
Nancy B Higgs says
I live in Houston and I have been trying to find out what to do about the white splotches for months. After the freeze in February 2021, I figured that would take care of it, but no it didn’t. Recently I showed leaves to Randy Lemmon, our Houston Garden guy. At first he said it looked like I spilled paint on them, then he saw a little red mite and said to use Spinosad. Even with spraying with Captain Jack’s Deadbug which contains spinosad, the mites never seem to go away. Maybe I need to try the horticultural oil now.
DeAnna says
Yes I would try the oil spray now that temperatures are cooling down. Then cut the plants back in the Spring