Like people, houseplants can contract diseases. Some are caused by bacteria, others by viruses or fungi. Here's how to nurse them back to health!
There are several diseases that affect houseplants. Here's a look at the most common and how to treat them.
Botrytis- Also known as Gray Mold, this fungus can be found on all parts of the plant. Begonias, African Violets and Cyclamens are particularly vulnerable to this disorder. Treatment consists of cutting away the affected parts and increasing air circulation. Remove any mold found on the soil, and spray the plant with a fungicide. Commercial versions can be found in any garden center, or you can make a homemade version by filling a spray bottle with water, a tablespoon of baking soda, and a teaspoon of vegetable oil.
Black Leg-This disorder affects stem cuttings and is caused by a fungus called Botrytis. The fungus invades the cutting and turns the base black. Affected cuttings should be discarded. To prevent, make sure your soil drains well and avoid over watering. Geranium cuttings are particularly prone to getting Black Leg.
Powdery Mildew- This disorder is found on the leaves of affected plants. It appears as a white powder on the leaves. Unlike Gray Mold, Powdery Mildew will not kill affected plants, but it will make them weak. To treat, removed badly mildewed leaves and spray the plant with a fungicide. To prevent, make sure plants have plenty of air circulation.
Leaf Spot- This disease is most often found on Dracaenas and Diffenbachias. It is characterized by moist brown spots that appear on the leaves. In severe cases, the spots merge and kill the entire leaf. Leaf Spot is caused by a combination of bacteria and fungi. The best treatment is to remove affected leaves, spray with a fungicide, and water sparingly for a few weeks.
Oedema-This disorder is also known as Corky Scab. It isn't caused by bacteria or fungi, but by the conditions the plant is in. It's characterized by hard cork-like growths on the underside of leaves. This is a reaction to being kept in low light and overwatered soil. Affected leaves should be removed and the plant should be moved to better light and watered less.
Damping Off-This is a rather common disorder affecting seedlings. A fungus attacks them at the base, causing the stem to rot and the seedling to fall over. To prevent, make sure your seedlings are in sterile soil, not over watered, and given good air circulation.
Root Rot- This occurs when plants are overwatered and the roots are deprived of oxygen. The roots literally rot away. The first signs are yellowing leaves and wilting. Eventually, the entire plant collapses. If caught early the plant can be saved. Treatment consists of removing the plant from its pot, removing the soil from the roots, and cutting away any roots that appear mushy and black. The plant can then be replanted in fresh, well-drainied soil. To prevent, don't overwater.
Viruses- There is no single symptom of viral infection. There may be stunted growth, deformed leaves and flower buds, and white streaks across flowers. Leaves will have pale green or yellow patches. Plant viruses are usually transmitted by insects or were already present when the plant was bought. Unfortunately, there is no cure. If your plant is showing signs of viral infection, throw it out. If you keep its pot, be sure to disinfect it thoroughly in a mixture of hot soapy water and bleach.
Fortunately most plant diseases are relatively easy to treat. Better yet, they can be prevented entirely by providing your plant with ideal growing conditions. If you do find signs of disease on your plants, act fast and follow the tips above and you stand an excellent chance of saving it!
The copyright of the article First Aid For Houseplants in Houseplants is owned by Susan Walsh. Permission to republish First Aid For Houseplants in print or online must be granted by the author in writing.
I have a Dieffenbachia in a pot that seems mostly healthy, with leaf growth
and a healthy shine on the leaves. It's in an approx. 6 inch pot, and I
just repotted it this spring so I know it isn't potbound. I water it only
when the soil is dry to the first inch deep, until it runs out the bottom,
and make sure it doesn't sit in it, etc. The only problem is that it drops
leaves. It isn't having a major impact on the foliage, and I don't even
know whether it's just normal plant aging, but it seems like every month it
loses about 5 or 6 leaves. But it doesn't look unhealthy in any other way,
and the leaf loss isn't impacting its appearance since it has so many other
leaves. Should I be worried about something, or is this just what
dieffenbachia does?
Aug 22, 2007 8:16 PM
Susan Walsh :
Hi there- Is your Dieffenbachia near an air conditioner or other
draft source? If so, that's likely the problem. Low humidity can also cause
leaf loss. If it's just the lower leaves however, then it's nothing to
worry about as it's normal for them to lose their lower leaves as they age.
Hope this helped!
Oct 28, 2007 4:19 PM
Loretto Taylor :
Help! I bought an aloe vera about two weeks ago- well, rescused it from
CVS. The soil was bone dry. I rewetted the root ball and put it in a new
pot- didn't really loosen the root ball.
Some of the leaves on a
couple of the plants are drooping and trying to fall over. They seem quite
fat- maybe too much water? I did let the soil dry out before I watered
again yesterday and now more of the leaves are drooping. Another
possibility I've considered i they are over crowded and should be
separated-there were about 3-4 largish plants in a three-inch pot, which I
put in a four inch pot.
I know aloes are tough, but after my
sorry luck with the mini-roses, I'm anxiously awaiting any advice I can get
before I try to do anything with the plant.
Oct 31, 2007 2:09 PM
Susan Walsh :
Hi! It sounds like it may be rootbound. Was the rootball more root
than soil? If so you can try carefully seperating the plants. Are the
leaves soft and mushy? That's a sign of overwatering. If they are
wrinkling, they are probably reacting to being underwatered for so long. If
they are still firm and smooth, then they just need more light. A western
or eastern window should do the trick. Good luck!
Feb 25, 2008 3:00 AM
arcticblonde :
I bought a Gerbera Daisy from a local nursery about a month ago to have as
an indoor houseplant. The leaves look droopy and now that the original
blooms drooped and died, I cut them off because there were new ones
emerging. Now the new buds at the base of the plant & the base of all
the stems/leaves are engulfed in this white fuzz. There is also white
powdery looking fuzz on top of most of the soil. The whole plant is droopy
and dying. Is there anything I can do to save it?
Feb 29, 2008 6:21 PM
Susan Walsh :
Hi arcticblonde. It sounds like your plant has powdery mildew. You can
treat with a commercial fungicide or make up your own-mix 4 parts water
with one tablespoon of baking soda and one part rubbing alcohol. Mix in a
spray bottle and spray as needed. To prevent in the future, be careful not
to overwater or keep the plant in a cool damp area. Good luck!
