How to Treat Ants on Orchid Plants

Ants are unwelcome visitors in your home, outdoor garden or greenhouse. However, ants alone typically do no harm to orchids. What can harm your orchid plants are the plant-sucking insects that the ants can bring with them and the diseases these insects might cause. If you catch an ant invasion early, you can easily resolve the problem with natural remedies.

Ants love to eat honeydew, which is a sticky excretion produced by plant-sucking insects such as aphids, mealybugs and scale. If your orchid plant has ants, you might be dealing with a type of "livestock" insect that excretes honeydew. To ensure themselves plenty of food, worker ants transport these livestock insects to plants such as orchids that they know their livestock insects will like to eat. When you identify the type of insects found with the ants on your orchid, you can start to control the infestation. After the livestock insects are gone, the ants will go away.

Aphids are small wingless insects. Many species exist and their color can range from yellow to green, red to brown, or even black. They use their mouths to suck fluids from plants, and this can kill a plant if left untreated.

Mealybugs are also small wingless insects with soft bodies. Most species are fuzzy and are typically white or grey. They congregate in sticky clusters on orchid leaves and on many other plants. Like aphids, mealybugs feed from plant fluids and excrete honeydew, which is prized by the ants that "farm" them.

Scale are hard-shelled insects, and there are many different species. You can easily mistake scale for tiny lumps or nodes on your orchid plant, but scale can cause extensive damage when they multiply. Adult scale insects are stationary, while the nymphs or juveniles move about.

Insecticidal soap for Aphids and Mealybugs: You can use insecticidal soap to control most plant-sucking insects, such as aphids and mealybugs. Insecticidal soap is available pre-mixed or in a concentrate that you mix with water before applying. However, you can easily make your own home-made insecticidal soap by following these steps:

Add 2 to 3 teaspoons of a good quality, non-ultra dish detergent to a clean, empty spray bottle. 

Fill the bottle with water and shake to mix. 

Spray the entire plant, covering all leaf surfaces.

Repeat the application every two to three days until all insects are gone.  

Horticultural Oil for Scale:Hard-bodied insects such as scale require an additional ingredient in your insecticidal soap. By adding one to two tablespoons of canola oil to your insecticidal soap, you can smother scale when you spray with this mixture. Commercially available horticultural oils are also effective in controlling scale.

Beneficial Insects:Insects such as ladybugs, lacewings, soldier beetles and parasitic wasps can be helpful in controlling harmful insects that have attacked your orchid plant. Beneficial insects are typically available through mail order sites.

A good location to release beneficial insects is near either an outdoor orchid or an orchid in a greenhouse, not near an orchid inside your home.

To control ants on your orchid plant, try sticky barrier products, such as "Tanglefoot," applied around the base of the plant. These barriers prevent ants from climbing onto your plant in the first place.