Help! What are These White Splotches on My Ruellia?

gillnurseryProblem Solving10 Comments

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. 


10 Comments on “Help! What are These White Splotches on My Ruellia?”

  1. Our mesquite tree leaves are covered with something that looks like this. Is it the same mite?

  2. 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.

    1. Yes I would try the oil spray now that temperatures are cooling down. Then cut the plants back in the Spring

  3. These are on my hibiscus and i just replanted some larger ones next to the regrowth of smaller will the large ones also get contaminated?

    1. You probably have mealybugs which is a different bug. Spray with Spinosad soap once a week for 2-3 weeks, If you have a heavy buildup on the stems, you may want to do a light cut back of the tips and then spray.

  4. Will thee mites affect all our plants? What can we do as a preventative measure to protect them?

    1. Hi Sally – yes it is too hot to use horticultural oil this time of year. If you choose to use Spinosad or Bee Safe, make sure the plants are well hydrated, and spray in the evening when its cooler.

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