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
Charlotte says
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?
DeAnna says
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.
Andrew F says
Yeah sounds like pink hibiscus mealybugs. Prolly a bit late to this reply. Getting lady bugs to get released and prevent the chemical treatment from eradicating the healthy insect is one way to treat. The other would be prune off the effected growth and bag it immediately. I find I can get control over it with bi weekly treatments of Bifen, and Imidacloprid along with some triple 20 to force green color and blooms.
Rita Vidal says
Will thee mites affect all our plants? What can we do as a preventative measure to protect them?
DeAnna says
This particular mite is specific to the Ruellia. Do not worry about other plants.
Jessica Spaw says
So is it powdery mildew or mites?
Andrew F says
The mites don’t need to be treated, if its caused by mites. They are just forcing the curling of the leaf, to create a habitat that is suitable for them. It wont be affecting all the growth. They don’t harm the plant, and it will encourage other beneficial insects into your garden to allow you have an organic self contained garden without the need for insecticides. Encourage your gardens to be self sustaining. Don’t hunt down solutions to a boon you would be squandering.
Andrew F says
You can get a jewelers eye piece, and check the growth on your plant yourself. You tell us, what it is please?!