Why Are There Ants Crawling on My Orchids?

Scientists claim that there are approximately 20 quadrillion ants on the planet. That is 2.5 million ants for every human on Earth! With those numbers, going through life without a few unwanted encounters with a colony or two is nearly impossible. When ants show up on orchids, there is usually a good (or bad) reason.

In most cases, ants don’t really care to eat orchids and typically don’t waste their time wandering about smelling flowers. The presence of ants on an orchid typically indicates an infestation of other insects. Let’s discuss the connection between insect infestation and the presence of ants and how to remedy both issues.

The Long Answer

You might see ants on your orchids for a couple of reasons, but the most common is insect infestation. A few different insects enjoy feeding on orchid sap, leaving behind a sticky and sweet excretion called honeydew.

Certain species of ants are very attracted to sugar and other sweet substances. Because they are hard workers, they recognize sugar and other sweet substances as energy.

Naturally, they are attracted to honeydew, which contains plenty of sugar, and they will continue to visit an environment where they know they can depend on its presence. It is not uncommon for ants to nest in the pots of plants that provide them with this important food source.

Several insects enjoy feeding on the sap of orchids, leaving honeydew in their wake. The culprits could be aphids, mealybugs, scales, or whiteflies.

1. Aphids

These small brown, black, red, green, or yellow insects prefer new growth, which they pierce with their mouths. This enables them to feed on the plant’s sap. Aphids reproduce quickly, so an infestation can quickly become overwhelming for a plant. Signs of aphids include the presence of the insects and their shed skins and curling or shriveling plant tissue.

Aphids are a huge source of honeydew for many sweet-loving ant species, and some species of ants have adapted to “farming” the aphids for their honeydew. Eliminating an aphid infestation can be much trickier if the ants keep carrying new aphids onto the plant! However, your diligence will pay off in the long term.

2. Mealybugs

You probably have a mealybug infestation if you see white, fuzzy bugs crawling on your plant or see the white waxy substance they leave in their wake. These serious pests can be very difficult to control and produce a lot of honeydew.

If there’s a small infestation, these typically require manual removal, so it’s important to catch them early to limit their spread. There are organic pesticides that can be used in large infestations, but those should be used sparingly.

3. Scales

Scales are the most serious insect issue for orchids. In fact, the mealybugs mentioned above are a type of scale insect, but here we’re addressing the “hard scale” insects rather than the “soft scale” type. Their lifecycles frequently overlap, and they reproduce quickly, making them difficult to eliminate.

Additionally, adults build a hard shell as they mature, which makes them even harder to eliminate. The adults are visible without magnification, so an infestation is typically apparent by looking beneath leaves.

4. Whiteflies

Adult female whiteflies lay eggs on the underside of orchids’ leaves. The nymph stage of the insect feeds on orchid sap and leaves behind honeydew.

Whitefly nymphs can kill an orchid if left unchecked, so it is important to control them as early as possible. The best way to detect whiteflies is to disturb the plant and watch for adult insects flying about.

How to Fix It

The best way to avoid insect damage and subsequent ant infestation is prevention. Most of these pests arrive in the home on a new plant with a current infestation. It’s crucial to inspect any new plants that are brought into the house, as well as purchase specimens from trustworthy sources. If you find insects, or evidence of them, on a new plant, isolate it and treat it before bringing it near your other plants.

Sometimes, prevention just doesn’t work. Perhaps the infestation on the incoming plant was still in the very early stages, and before you knew it, they were jumping all over the place. When this happens, try to isolate any infected plants while treating them to stem the spread.

Orchids are sensitive to chemical insecticides, so it’s best to avoid using them if possible. Neem oil is a good treatment for most of these pests, as is manual removal.

Isopropyl alcohol is another valuable tool in the fight against insect infestation. Using a cotton swab dipped in rubbing alcohol, wipe away the insects without harming the plant.

Sometimes the insects are so established on the orchid that they can’t all be seen. Thus, they are difficult to reach and remove. If all else fails, an insecticidal soap may be necessary to eliminate the infestation.

Now What?

Now that you’ve hopefully gotten the other infestation under control, it’s time to address the ant situation. While ants will not actually cause any harm to your orchids, they can be a nuisance, particularly when their primary food source is eliminated. Ants on the hunt mean they are in other parts of your home.

As we discussed, orchids can be sensitive to chemical insecticides, and we don’t want to inadvertently kill our orchids trying to eliminate insects that aren’t truly harming them. Nonetheless, if your orchids are indoors, getting rid of the ants is a good idea.

The first thing to try is to flush them out. There is a good chance that they will have taken up residence in the potting medium, and thoroughly wetting the medium will help remove many ants.

If the infestation is mild, this might do the trick entirely, as ants don’t like to live in wet soil. Just run a strong stream of warm water over the roots and potting medium and wash out as many as possible. Repeat this every few days for a week.

There is a possibility that the ants may have laid eggs in your potting mix, and if this is the case, it is best to change that altogether. While you’re at it, make sure to rinse the pot really well with soap and hot water. As an added precaution, setting some ant traps nearby is a good idea to draw the ants away from the orchid.

Fun Fact: Orchid-Ant Symbiosis

There is one type of orchid, Caularthron bilamellatum, which is classified as a Myrmecophyte. This means it has adapted to live with ants. This orchid, found in the forests of Central America, literally provides food and shelter for an entire colony of ants on purpose.

The plant produces nectar not only from its flowers but also from the pedicel, seedpods, leaf bases, and developing shoots! This nectar provides nearly half the food the ant colony needs for an entire year. The orchid also houses the ant colony in its pseudobulbs.

As to why the plant has evolved to have this relationship with ants, we consider what the ants have to offer the orchid in return for the bed and breakfast. One theory surmises that the ants offer the orchid plant protection from hungry herbivores who prefer to eat plants that are not full of biting ants.

The relationship has been studied to prove that the ants actually produce and distribute valuable nitrogen throughout the plant, acting as living fertilizers! Isn’t nature fascinating?

Final Thoughts

If you see ants on your orchids, chances are there is another insect at play. Protect your orchids by carefully inspecting new plants before introducing them into the environment. If infestation crops up, isolate the plant and deal with the harmful insects first. Ants won’t harm the plant; they’re just a nuisance in the home.