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
N says
Will neem oil work on this?
Jesse Jenkins says
Yes – neem oil or Spinosad soap if you want to cut back and treat this Fall. Or wait until January and use All Seasons Horticultural Oil which is heavier and should be used when temps are cooler.
Joey Santiago says
Out of curiosity would dish soap and water work as well to kill the mites? Thank you
Jesse says
Hi Joey. We doubt that regular dish soap would be effective. Horticultural oil is effective because it’s heavy and suffocates the mites. Spinosad soap contains Potassium Salts of Fatty Acid (18.8%) and Spinosad (0.1%) which act to kill the mites.
Joey Santiago says
Understood thank you very much.