I’ve talked before about insect problems on vegetables, but other insect pests may also be found on indoor or outdoor plants, including flowers.
Common Pests and How to Handle Them
Here is a list of some of the more common ones and what you can do about them.
Spider Mites
If you see tiny white or yellowish spots on your leaves or fine white webbing on stems or the backs of leaves, you may have spider mites sucking on your plant juices. Spider mites are particularly fond of thin leaves—you generally won’t find them on plants like rubber trees, etc. with thick or waxy leaves. Palms seem to be particularly prone to getting them. Spider mites like it warm and dry so indoor plants during the winter tend to have more problems with them. Taking your indoor plants to the bathtub several times over the winter and giving them a good shower can minimize damage. When spider mites are suspected in outdoor plants, a good spray from the garden hose can help. An insecticide such as Neem Oil or Insecticidal Soap can help.
Mealy Bug
Mealy Bugs look like little white fuzzy pieces of cotton lint. They suck on plant juices and are particularly fond of citrus and some succulents. I’ve had a beautiful hoya (wax plant) for over twenty years and have had to clean it of mealy bugs several times. If you have a minor case, dipping a Q-Tip in rubbing alcohol and “dabbing” the pests off can help. Because rubbing alcohol can actually damage some plants, they recommend using Insecticidal Soap or Neem Oil.
Scale
Scales look like little beige or brown “bumps” on the leaves or stems that you can pick off with your fingers. The best way to remove them is to physically remove as many as possible, then spray the whole plant with either Neem Oil or Horticultural Oil. The oil coats the scales and “smothers” them.
Aphids
Tiny sucking insects in several colors that tend to cluster on new stems, the backs of leaves, etc. They can easily be eliminated by a nice “aphid” bath—mild soapy water washing off colonies. Neem Oil and Insecticidal Soap are also effective. Nasturtium, sunflowers, and marigolds are good “trap” crops for them outside. You’ll still need to treat the plant, but it’s better than treating a whole row of peppers, for example.
Fungus Gnats
Fungus gnats lay their eggs on decaying organic debris in the soil. They’re particularly a problem on indoor plants. If you have fungus gnats, it’s almost always a clear signal that you are overwatering! The soil for indoor plants should almost always dry out an inch or more down between waterings—just not so dry the leaves wilt or curl. In larger pots, your soil should be dry two inches or more down. Certain plants, like cacti and succulents, should dry out almost completely between waterings. If you buy your plants from a garden center, they will probably know how you should take care of them, or you can look them up when you get home.
White Fly
Usually found in clusters on the backs of leaves, they fly off when disturbed. They’re related to aphids. To get any eggs, wipe off the backs of leaves, then spray with Neem Oil or Insecticidal Soap. They hate cold, so they tend to be found more on indoor plants in Zones 7 and higher.
Catch Insect Problems Early and Get Professional Help if Needed
Many insects are out there, but these are some of the most common. As always, when dealing with a plant problem, catching it early is the best thing you can do. If you do discover a pest on a potted plant, isolate it from others if you can. If you aren’t sure, you can always bring a leaf or two to us to look at.