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Please Help! I’ve Got Fungal Gnats

Please Help! I’ve Got Fungal Gnats

So, what’s up with Bradysia or as we better know them – Fungal Gnats?

These little flies are part of the Diptera order which includes mosquitoes, and part of the Sciaridae family of dark-winged fungus gnats.

You might spot them when you’re browsing your phone or having a coffee because they tend to irritatingly hover around your face. Get out of my personal space! It’s because they love the carbon dioxide you’re breathing out.

Unfortunately for us, fungal gnats also prefer temperatures between 17 - 25 degrees Celsius which is the temperature of most households. A damp plant pot in a snug warm home is the perfect breeding ground for fungal gnats.

But does it actually matter? Aren’t we supposed to love and encourage insects?

Why Fungal Gnats Are A Problem

Here at PIAB we have a ‘live and let live’ motto, but fungal gnats have the potential to destroy our beloved plants and we can’t have that kind of behaviour.

Fungal gnats are plant killers because they damage the fine root hairs on your precious plants. They spread nasties such as Fusarium, Pythium, Phytophthora and other fungal diseases.

Sorry gnats you’ve got to go.

What Are They Even Doing In My Home?

Fungal gnats eat fungi – big surprise huh?

They also chow down organic matter in the soil, the fine hairs on plants, and algae – all of which are found in your plant pots. They prefer the top three inches of soil so you won’t have to dig far to find eggs and larvae.

Yes, that’s right, fungal gnat larvae live in your plant pots.

Adult flies lay around 300 eggs over their short lifetime, and those develop into squirming larvae (hope you’re not eating right now). It only takes four weeks for those 300 larvae to grow wings and fly the nest.

You can see how infestations quickly get out of control.

It gets worse.

Flying isn’t the only way they spread!

Fungal gnat procession/migration is rarely seen and no-one understands it, but those wrigglers can suddenly up sticks and leave en-masse to search out a new abode.

Imagine those crawling across your coffee table – Ewww! Don’t worry though this is a pretty uncommon event.


Get Out! How To Treat Fungal Gnats

Your beautiful foliage needs help. Here are a few ways to shift out those unwelcome squatters.

Let’s start with sprays.

1. Neem oil mixed with water according to manufacturer’s instructions is a good way to kill larvae. Spray soil and roots liberally until its drenched.

2. Mix 1/2 Apple cider vinegar, 1/2 water, and a small squirt of organic washing liquid into a small bowl and place it on top of the soil. Adult flies can’t leave it alone and end up falling in. Much like us unsupervised around chocolate fountains.

3. 3% Hydrogen peroxide mixed one part to four parts water on dry soil will fizz and kill larvae on contact.

If you have a huge infestation you may need to remove the plant, treat the roots, and re-pot your babe in fresh potting mix. Make sure you buy a quality potting mix, sometimes these little critters are already lurking in the bag.

Science Nerd?

If you like science try Bacillus Thuringiensis. It’s a soil-borne bacterium that produces toxins fatal to certain insects. Buy it online and follow the instructions to create your own plant army.

More of a builder-type?

Build a barrier of food grade diatomaceous earth, washed sand, clay balls, or gravel so the flies can’t lay eggs in the first place. You can also hang yellow sticky traps to catch the adults.

Post Fungal Gnat Infection Tactics

Once those unwanted pests are gone, implementing some preventative tactics will keep them out for good.

One of the best ways is to make your plant pot an unattractive place to live.

It’s good practice to let plant soil dry out a few inches at the top so you don’t overwater them, and this also creates dry conditions that fungal gnats hate. They’ll look elsewhere for a des-res if the soil is dry.

If you have trouble keeping on top of a watering cycle try a Sustee.

You can also give roots a drench every couple of months with Neem oil and water just in case killer fungal gnats are sniffing around.

So that’s fungal gnats for you. We can’t stand them chewing on the roots of our precious babes. Roll up your sleeves and turf them out too – your foliage will thank you for it. 


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