Fungus Gnat

02 Jul, 2021

Sciaroidea family. Also known as fungus flies, these small, winded insects hang around damp soil or new plants that are planted in rich organic matter.

The gnats themselves do not do any harm to the plant and only live for up to three days, but in their larvae stage they tend to feed on material in the soil and roots.

The larvae are white, 3-4mm long and can cause damage to tender or, in cases where there is already damage, rotting roots.


Soil that is too wet is a perfect breeding ground for fungus gnats.

Keep your indoor plants (other than ferns) on the dry side and water sparingly. Check the moisture of your soil by sticking your finger into the soil, if your finger comes out clean it means it is ready to water. Also, if you are able, gently lift the pot to check its weight. If the pot is light, you can water your potted plant.

A moisture meter can help you use the correct amount of water. Leave a single meter in the same plant’s soil, otherwise the meter can become inaccurate.

Keep outdoor pots in warm or sunny positions so the soil is not wet for the remainder of the day.

Organic Treatment

If able, let the soil dry out for longer between watering.

Spray around the affected plant’s roots with DEEM spray. This product is organic with a blend of Debug and small amounts of neem oil.

Sundews are sticky carnivorous plants that can also keep fungus gnat numbers to a minimum.

Other Option

Spray Houseplant Insect Control Spray around both soil and plants for gnats.

Oil sprays can harm palms and ferns, spray DEEM around the roots instead.

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