The Chase star and quizzer extraordinaire Darragh Ennis has shared a simple and effective way to keep your houseplants healthy and free of any unwanted pests and flies. As the spring season ushers in good weather for growing plants, a common side effect is attracting the attention of unwanted pests.

In a recent TikTok video, Darragh explained that small black flies have been appearing on and around his houseplants. As an entomologist, Darragh shared his love for insects, but that he doesn’t want them congregating throughout his house. He acknowledged that they can be particularly tricky to get rid of, too.

These types of flies, he explained, are known as fungus gnats, as they live in compost and soil. Darragh said: “Getting rid of them with chemicals is really hard, and if you wanna keep your houseplants and get rid of them, you can use something called nematodes.”

What are nematodes?

You’d be forgiven if you haven’t heard of nematodes, but many green-fingered gardeners use them as an alternative to chemical pest deterrents. Nematodes are tiny microscopic worms which can get rid of unwanted plant pests thanks to them carrying lethal bacteria.

The creatures act as a parasite on other insects, releasing the bacteria into the host’s body to kill them, before they feed on them.

Garden Organic noted that nematodes can be more effective than a chemical deterrent as they won’t “drift off target”, as they are “specific to the host pest”. Nematodes can be used to kill a range of pests such as caterpillars, beetles, leatherjackets, ants, slugs, chafergrubs, fruit flies, carrot root fly, and onion fly.

To make sure the nematodes take proper effect, you should read the detailed instructions on the back of the packet. However, Garden Organic explained there are a few general rules to follow, including:

• The soil needs to be above 5℃ (and remain so, even at night).
• The pests or their larvae need to be active (generally, this is during spring and autumn).
• Nematodes are light-sensitive so should be applied when light levels are low in the very early morning or at dusk.

When it comes to houseplants, Darragh instructs to pour the packet of nematodes into a watering can. Then follow by pouring the water over each of the plants and their soil.

He said: “The best bit about this is it crawls through the soil and hunts through the larvae and everything so they’re gone. So if you want to get rid of those little flies and you don’t wanna put loads of chemicals on, buy some nematodes.

“Studied them for my PhD, now they’re useful in my house.”