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Help! What are These White Splotches on My Ruellia?

ruellia mites for blog

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

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Comments

  1. Debbie says

    So finally I have found out what is happening to mine. At first I thought they were mealy bugs but they’re not bugs. It’s like this white stuff all over them. So with it being mid-summer do you recommend just going ahead and cutting them down? I’m feeding the ground?

    • Jesse Jenkins says

      Yes, you could go ahead and treat with Spinosad Soap or Bee Safe, then cut them down and regrow. Don’t use horticultural oil in summer though because it will burn the plants.

    • Jesse Jenkins says

      Hi Pamela – we’re not sure yet whether these mites will infect other plants. So far we’ve just heard about and seen them on ruellia. But when you treat them and cut back the ruellia, you decrease the chances of them being able to infect other plants.

  2. Kim says

    In FL and the heat is unbearable, so we never thought mites. Ty for the info we’ll try the oil treatment. These plants are less than 6 months old. 🌷🌴

    • PCBTom says

      I am also in FL, the panhandle, and I had this last year on all of mine. I cut it all down in Oct and let it go. Most places are ok this season. There have been a few plants starting to show a little white. I have cut those at ground level. Some have grown in ok …so far! As hardy as this plant is I have tried in the past to eliminate it in a few areas with “R-U” weed killer but it comes back! Tough stuff to kill once established! I will say that in those areas it grows back without the white!

  3. Kerry says

    I live in Naples, FL. I planted Ruella about 6 months a & love them .. They’re now tall and have been blooming for several months .. Suddenly they’re covered in that white powder “stuff” and I can see some of the leaves are distorted.. Should I cut them down now ( September ) and if so, how far down ?? I’ve tried a spray from a local nursery without any success .. Thanks for any suggestions ..

  4. Tami says

    What causes them ?to wet, to dry ,not enough sun ,shade ? Because we have a lot of different junk on our bushes and it just seems like if a plant is going to get sick it will happen in our yard!!! I have never had such a problem with these fungus and or mites. We live on the nature coast of Florida

  5. Deanna says

    Having the same problem in Jacksonville Florida, my Ruellia is normally healthy and flowering, just bought some new one from nursey and they also had the white on leaves. One plant is usually full of flowers but they are sparse now. We need some kind of solution for these pests. Its so hot here now and nights are warm as well what should we do now

  6. Chrissy says

    I live in Florida and have the same issue with my Ruellia. Should I use neem oil or spinosad in the evening? Thank you ????

    • Jesse says

      Hi Chrissy – we recommend treating with All-Seasons Oil Spray (a horticultural oil), ideally in the winter months. Repeat the treatment every 5 to 7 days for a total of 3 treatments, then wait until Spring and cut the plants down to ground level and they should grow back nicely.

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