How to Treat Powdery Mildew on Your Pilea
As a plant lover, there are few things more demoralizing than noticing that your beloved plant baby is being attacked by a disease or a pest. And when you’re fighting something as small as a fungus, as is the case with powdery mildew, the heartache is real.
The good news is that Pilea plants are not particularly prone to mildew, and they can easily bounce back when attacked. The bad news is that you’ll need to be persistent in your treatment, especially if you’ve decided to keep your Pilea outdoors or if there’s a high temperature variation between day and night in your plant’s environment.
Here’s how to diagnose powdery mildew in Pilea.
First of all, make sure what’s attacking your Pilea is, indeed, mildew. Quite evident in the name, powdery mildew manifests itself as a powder-like stain (either white or grey) on the underside and the surface of leaves. Sometimes, the powder may also travel down the stem of your Pilea. If you rub the affected surface, some of the powder will come off on your finger.
However, diagnosing the correct pest is not as easy, as there are a few other afflictions that look similar. One common misdiagnosis is mealybugs, another powdery material that shows up on the leaves out of nowhere. But if you look closer, you should be able to see the individual mealies in this type of infestation. Mealybugs make a protective dusty coat that they nest in, which makes them resemble mildew. When it comes to mildew, there will be no individual bugs crawling around, just a coating of powder.
Before we move on to how to best treat mildew on your Pilea, let’s have a look at what kind of environment makes it more likely for your plants to develop mildew.
Powdery mildew is a fungus that proliferates through spores. It can simply blow in through an open window, hitch a ride indoors on your shoes or clothes, or be burrowed in plants that you’ve recently purchased and brought into the house. It prefers an unventilated cool moist environment, and it can cause irreparable damage to your Pilea if left to spiral out of control.
How to treat mildew in Pilea
Step 1: Isolate your Pilea as soon as possible.
The minute you notice even the most subtle sign of infection, you must isolate the plant away from your other houseplants. Powdery mildew is species-specific, meaning that the cgi that caused it on your begonia will probably not cause it on your Pilea too. However, several species of plants may develop a simultaneous infection if the conditions are just right.
Step 2: Remove and discard the most affected parts.
If there are leaves that have been badly affected and turning black, then it makes more sense to remove them. Once a leaf turns brown, black or yellow, it will not heal itself back to green. This will also lower the count of fungi and slow down the spread of the disease.
Step 3: Salvage what you can.
If there are leaves that only have a few specks of mildew, congratulations - you’ve caught it in time and these leaves are salvageable. After all, if we had to throw away the entire plant every time there was an infestation, this houseplant keeping would turn into a very expensive and quite unrewarding hobby.
Here are three solutions you could try, in order of severity. Go down the list and try the first solution (the mildest), then take a couple of days to observe if the solution worked. If you still see signs of mildew after two to three days, try the next solution.
The trick is to be thorough and clean the leaves, the petiole and the stem as well as possible. After handling an infected plant, make sure you wash your hands thoroughly and disinfect any tools you may have used to deal with the plant.
Wipe the leaves with a cloth soaked in soapy water. It’s better if you use dish soap as opposed to regular lye-based soap. A few drops of soap in a spray bottle full of water should be enough.
Wipe the leaves with a cloth dipped in a mix of water, baking soda and dish soap. Again, a teaspoon of baking soda should be enough for a spray bottle’s worth of water. Spray the solution on the leaves of your Pilea, both on top of it and on the underside of the leaf. This solution will leave marks, and some growers leave them on intentionally to coat the surface of the leaf and prevent the mildew from attaching to it. You can wipe it off, but this might diminish its efficacy.
Wipe the spot affected with neem oil. Neem oil is a natural fungicide, but used in excess it will also clog the pores of your plant. That’s why we don’t recommend a spray dousing, but a gentle wipe with a cloth that has been dipped in neem oil. While it’s not the cheapest solution, even a small bottle of neem oil will go a long way, and it will last for years if stored in a cool, dry place.
Dilute some rubbing alcohol into water and spot-clean the mildew. Alcohol kills mildew, but it will also damage your plant’s leaves if you coat it in it. Take a q-tip and dip it in diluted alcohol then rub it over the spots that are most affected by powdery mildew.
If nothing else works, as a last resort, you can apply a fungicide specially designed for houseplants. Make sure to follow the instructions on the label, and always relocate the plant to a well-ventilated outdoor space before you spray anything on it.
Step 4: Tweak your environment and plant care.
You want to prevent powdery mildew from forming in the future, so here are a few other changes you need to make to how you care for your plants.
Powdery mildew thrives in stuffy, stagnant air. Move your Pilea to a well-ventilated space. First, make sure your Pilea is in a spot where it gets a lot of airflow without getting direct drafts. So not directly in front of an open window, but not too far away from it. If you have a tendency to overcrowd your houseplants, leave some room between the pots and make sure that there’s extra room around the foliage.
While you’re dealing with powdery mildew, avoid giving your plants a shower. While we’re the first to recommend putting your plants in the shower to remove the dust that collects on the leaves, if your Pilea is suffering from mildew, switch to wiping its leaves with a damp cloth.
If you’ve been misting your plants (we don’t recommend that for most environments), stop immediately. Misting is good for some plants under certain conditions - if you’re living in the desert and want to grow lush foliage, misting may be necessary. But under most circumstances, misting does more harm than good, as it keeps the leaves artificially wet (as opposed to wet from normal leaf perspiration) and promotes the growth of fungi.
Powdery mildew, as unsightly as it may look, is not your plant’s worst enemy. But it is a good idea to catch it early and try to eradicate it as soon as possible.