White chalk-like fungus/substance on plants

10 years ago

I need help identifying a white chalk-like fungus or substance of some kind that consistently seems to plague certain plants that I grow in my house. As the attached photo shows, the two palm plants are the worst affected, and they can become almost completely covered if I don't wash this chalky white substance off every couple of weeks. It does not seem to harm the plants much, and it reproduces very fast. Some plants seem to be unaffected, but I can't tell whether it's because of their position or their species.

I have tried spraying with two different kinds of commercial Fungiside (Safer Brand and Garden Safe) but neither seemed to have any effect.

Can anyone help me identify what this substance is, and how I can get rid of it?

Featured Answer

Tiffany, purpleinopp Z8b Opp, AL

10 years ago

Drew, welcome to Gardenweb!

I'd hope this is a good news/bad news situation. The bad news is that it looks like mealy bugs. The good news is that if that is what it is, an insecticide known to treat such a pest should work much better than fungicide. Do any of the spots move?

The fact that your plant has something wrong with its' health leads me to be concerned about possible root rot and/or tap water poisoning, which are somewhat related problems, but each of which could weaken a plant and make it susceptible to attack. The cause of these problems is often water sitting in a drip tray and/or soil that takes a really long time to dry out. The leaves look a little chlorotic, which would be another symptom of problems with tap water chemicals. Many people try to catch rain water, or use distilled or the condensation from a dehumidifier for at least the sensitive plants, for these reasons.

Changing the soil and removing any dead roots is also usually very helpful toward fixing these issues. From that point, watering where the excess water can drain away can also be very helpful.

Would you be able to include a pic of the whole plant?

What other plants do you have with this symptom?

If your palm is Chamaedorea elegans, I can attest it's quite sensitive to tap water chemicals, which will manifest as yellowish leaves over time.

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Comments (17)

DrewStoddard
Original Author
10 years ago
Thank you for your very helpful response. The spots do not seem to move, but your suggestion of mealy bugs seems to be the best answer anyone has come up with so far. The way the white substance spreads does seem to indicate insect behavior. I will try an insecticide and see if that works.

On the broader subject of tap water poisoning, this is the first time I have heard of this and it is extremely useful. Several of my plants look as though they are becoming sick, and this happens after I water them with tap water for about 4-6 months. I am going to start watering them with spring water which I have delivered for drinking. I don't know if it's a pure as rainwater but at least it will be different and it will be interesting to see if there is a change.

Thanks again for all of the helpful information. I really do appreciate the time and effort. :)
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Tiffany, purpleinopp Z8b Opp, AL
10 years ago
You're welcome. HTH! Don't forget the dripping out is as important as the water (or what may or may not be in it.) Going outside in the shade to enjoy the summer humidity might be appreciated by the plants also. Sending good vibes!
Laura Forero
7 years ago
Has the problem been solved? I have a very similar problem on a Strombili plant. I am sure it is not a fungus because it doesn't have a hyphal mass or any hyphal growth in general. Rather, they are small rod like structures. Like white rice.
rhizo_1 (North AL) zone 7
7 years ago
Laura, I suggest that you start a new thread rather than piggy-backing on someone else's. Pictures will certainly help you get an accurate diagnosis.
Diane Romanov
6 years ago
Thank you for posting this question and Tiffany for the answer! Very helpful!!
Andrea ME z5b
6 years ago
@Tiffany, what do you mean by "tap water poisoning"?
Tiffany, purpleinopp Z8b Opp, AL
6 years ago
Chlorosis from over-exposure to lime, chlorination, fluoride, anything else in water that might make a plant ill &/or alter the PH of the soil.
ian_elder001
6 years ago
Can anyone tell me what this chalk / rice like substance on my palm plant and how to get rid of it? Thanks
Tiffany, purpleinopp Z8b Opp, AL
6 years ago
Ian, your plant has some kind of bugs, I can't see them clearly enough to see exactly what they might be.
Luis Godinho
5 years ago
last modified: 5 years ago

Doesn't
User
5 years ago
Drew my palm looks the exact same as your first pic. Were you able to fix the problem? If so what worked?
Dollie Jacinto
5 years ago
last modified: 5 years ago
I once had this problem until I started spraying with dawn dish soap and water. Seems to work. Inspect them every couple of days or so and spray generously until gone. It takes work but worth the effort. You should also cut off the infected branches and spray where the growth (closer to roots) starts. This is the area where these bugs live or colonize (so to speak).
gardengal48 (PNW Z8/9)
5 years ago
Ian's problem is also mealy bugs but Luis' is showing a scale infestation. Different control strategy required for that but easily researched. Horticultural oil is usually the go-to for scale.
Kathy Smith
4 years ago
last modified: 4 years ago

Mine is similar to the first pic, attaching here? Is it a bug also?
Michael Mccabe
2 years ago

Help, what is it and what do I do? It's my first palm.
ken_adrian Adrian MI cold Z5
2 years ago
the entire point of pulling up an old thread.. is to read the thread for the answer ... its all up there ... palm smack to forehead ....

White chalk-like fungus/substance on plants

Tiffany, purpleinopp Z8b Opp, AL

Comments (17)

DrewStoddard
Original Author

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White chalk-like fungus/substance on plants

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DrewStoddardOriginal Author

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DrewStoddard
Original Author