It sounds like your roses may have powdery mildew. If possible, remove the infected leaves and treat the rest of the plant with a fungicide, which you can find in your local hardware store, garden center, or online. Powdery mildew forms when conditions are warm and humid, so if you happen to be watering your roses from overhead, try watering at the base of the plant instead to reduce moisture around the leaves.

Have you contacted the source from which you purchased the plant? It may have been diseased or at least your vendor may have been able to provide some guidance. These are tropical plants that are vulnerable to a number of pests. That said, it is not a plant with which we have any experience, and would advise you to read up on it here: https://hort.purdue.edu/newcrop/morton/soursop.html (Perdue is an excellent resource). We would also suggest that you contact the cooperative extension nearest you (chick on your state here: http://www.almanac.com/content/cooperative-extension-services ) If the folks at the extension do not have an answer they may very well refer you to a colleague at a service that is knowledgeable.

If you are talking about potted plants, it could be a harmless (and common) fungus called saprophytic fungus. It usually results from a combination of over watering, poor drainage, and old or contaminated potting soil. If any or all of those conditions ring true, repot the plant with new soil (and possibly a pot that drains better) and water less frequently.

Hi Shirley,

There are a number of plant species with the common name of moon flower, but I am going to guess you have a Datura plant, in which case you may be looking at any one of the following viruses: Datura wilt virus, Datura distortion mosaic virus, Datura rugose leaf curl virus, or Datura quercina virus–all exhibit the wilting symptom. It is important to know if it is a virus and which one it is before treating it. I suggest taking some tissue cuttings (leaves and stem) and sending the sample to your local Cooperative Extension Office for testing. They will tell you a course of action to take.

It’s hard to say for sure, but what you describe sounds like powdery mildew fungus, which won’t kill the tree, but can be unsightly and might compromise the tree’s long-term health, if allowed to spread. Go ahead and remove that branch, then monitor to see if the spores are spreading. There are a number of non-toxic products on the market for treating it, and even a few home remedies!

If you notice mold turn the soil over and bury the mold. Keep the soil as dry as possible and only water the individual plants not the entire garden. It also helps to add new fresh soil to the garden if the mold issue doesn't go away.

Hi, Jennifer: Just to be on the safe side, sure, go ahead and remove the affected soil, then proceed as usual. Mold is everywhere, though, and usually doesn't pose a problem in soil, as it will dissipate once its growing conditions (organic food, a lot of moisture) deteriorate. Mold on plants is another matter, as you recognize, as is nonwhite mold. Thanks for asking!

Hi Branden,
We suggest that you remove the plant from the pot. Discard any soil that has mold on it and replant in a new bigger pot with light potting soil for containers.

Hi, P.J.: Excellent question! From a technical standpoint, the answer is yes. Assuming that you mean a leafy veggie, and not something that you would peel or de-pod anyway, it is indeed possible to wash them thoroughly enough to eat (say, with a very weak bleach solution, then assiduous rinsings), especially since some might end up being boiled anyway. From a practical and 100% safety standpoint, though, we wouldn't do it.

Hi, Lea: Meet powdery mildew. Before doing anything drastic, just try washing it off with a water spray. (Some folks say plus milk, and/or plus baking soda, etc.; we say keep it simple, at least to start.) Do it in the morning so that the leaves have time to dry out before the humid part of the day, humidity being the main culprit, not water itself.

It sounds as if you may be watering too frequently. Make sure that you aren't saturating the soil; let it dry out and then deeply water and then let it dry out again between waterings. Take the seedlings off any watering trays so they're not wet on the bottom; let them drain and put on a cloth. You can scrape off the white mold; if it gets too bad, you might need to replant the seedlings in clean soil. You could also consider an anti-fungal product; ask your garden center. Finally, some readers suggest adding a little sand and others say sprinkling with cinnamon helps!

To prevent white mold, avoid wet soil or overwatering. Just keep soil moist.
Use raised beds.
Create furrows in the soil for watering or irrigation so that the water doesn't just flow all over the bed surfaces.
Do not water from overhead and get the plants wet; water at the soil line.
Space plants extra far apart to allow good air circulation.
Remove and destroy entire infected plants and crop residues as soon as you see any signs of mold.
Hope this helps.