Controlling Fungus Gnats

How to control Fungus Gnats

Ever wondered what those tiny black flying insects are buzzing about in small groups around your indoor plants? Fungus gnats (Sciaroidea family) in their adult form can be most annoying invading our interior space in large numbers. But it is their larvae which do the most damage to plants’ roots. Adult flies lay hundreds of eggs at a time in the plants’ soil and their eggs hatch into white worms-like larvae featuring black heads, wreaking havoc by feeding on the roots and soft stem material of the plant, seriously weakening its ability to survive. The Fungus Gnat’s life cycle from egg to adult flies is just three weeks.


To detect larvae presence, gently dig around the soil for evidence of the worm-like creature. They can also leave a silvery shiny trail on the top layer of the potting mix, similar to snails and slugs.  



Tips to controlling Fungus Gnats


• Fungus Gnats love moist wet soil where they can thrive in great numbers. So be careful not to over water pot plants and let the soil dry out between watering. This will greatly reduce the numbers of eggs hatching and larvae feasting.


• Stop their life cycle by hanging sheets of sticky traps close to the indoor plants to kill the adults before they have a chance to lay their eggs in the soil.


• A physical barrier can also be created to stop the adults accessing the soil to lay their eggs. Mulch thickly over the top layer of soil with stones, gravel and small pebbles.


• To control larvae and stop eggs hatching in the soil, dunk the pot plant in a half strength solution of Searles Conguard. Leave the pot plant in the solution until the soil is fully soaked with the solution and then remove to drain. Repeat process after 3-4 weeks if necessary.


Searles Gardening Fungus Gnat trapped on sticky trap


Searles Gardening Fungus Gnat Adult Fly

Control Fungus Gnats