Harmful insects Houseplants

When Aphids Attack Houseplants

Hibiscus flowers infested with aphids. Photo: Shnurochek13, depositphotos

By Larry Hodgson

Question: My hibiscus and my flowering maple spend the summer outside. For 2 years, I have noticed that during their stay indoors over the winter, some of the flower buds become full of aphids or mealybugs. I’m not sure which. They’re never found on the leaves or stems, but only the flower buds before or as they open. The infestation lasts until I put them outside again in the spring for their summer outdoors. What should I do? I’ve tried insecticidal soap, misting, spraying with olive oil. Nothing works.

Do these little critters also have something to do with a little fly with very long wings that has been wandering around the house since the beginning of autumn? It mostly sits in the windows of the room where the plants are.

Rose

Answer: The large number of insects and their presence only on the flower buds and flowers suggest you have an aphid infestation rather than one of mealybugs, as the latter are a little slower to multiply and prefer to settle on longer-lasting plant parts like stems and leaves rather than flowers. Aphids prefer soft tissues, so flowers are very much to their liking. And they proliferate exponentially; their number can increase more than tenfold in a week. Thus, if a single insect survives any treatment you give, the infestation will quickly resume.

The secret in controlling aphids is to be as methodical as possible. Start by removing the affected flowers and buds as soon as you notice them. Then, rinse the plants with a very strong spray of water (in the sink or the shower), turning them in all directions so that the water can reach every nook and cranny. Next, spray with an insecticide. Safe ones to use indoors include insecticidal soap and neem oil. (Don’t waste your time with olive oil.) Repeat the treatment the following week, even if you don’t see any insects. Then repeat two more times, always weekly. By repeating the treatments and always being thorough, you ought to be able to eliminate the invaders.

Green lacewing
The lacewing is a beneficial insect that helps control aphids. Photo: artsehn, Pixabay

As for the fly with very long wings, it could be winged aphids (aphids normally do not have wings, but produce winged individuals on occasion, especially in the fall), but usually their wings don’t seem overly long. I’m not at all sure, but it might be a lacewing, an insect that is an aphid predator and sometimes enters homes in the fall seeking shelter from the cold. If so, just let it do its thing, as it could help you by consuming any aphids that escape your treatments.

5 comments on “When Aphids Attack Houseplants

  1. Good luck with that! I had the same issue for several years and tried numerous approaches. Finally decided it’s impossible to fight the aphids on my indoor hibiscus. I just moved them away from all other plants, banishing them to an out-of-the-way location.

  2. This is the time of year the aphids always seem to show up too. My overwintered potted rose bushes in the garage are just starting to bud and have to check them every day to wipe off the pesky little things.

  3. Barbara Curson

    We use too many insecticides.

  4. Mark Gold

    I believe ladybugs can also help. They have become available commercially.

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