Indoor Plant Insecticide For Gnats

Interestingly enough, a common household item is one of the top recommendations that I have for controlling these pests. Hydrogen peroxide (the standard 3% topical variety) can be used as a soil drench.

Mix one part peroxide with four parts water, and pour it through the soil at the root zone until it begins to come out of the base of the pot. The peroxide kills fungus gnat larvae on contact.

Neem oil is also an effective soil soak to combat fungus gnat larvae. Dilute the oil with water per the manufacturer’s directions and directly drench the soil at the roots of the plant. You can also spray the upper portion of the plant to keep adult gnats at bay.

Concentrated azadirachtin naturally occurs in neem oil. It’s safe in hydroponic use as well as in greenhouses, gardens, and indoors. Use it per the manufacturer’s directions in the same way you would use neem oil.

Pyrethrin sprays are also effective against fungus gnats and their larvae. To use pyrethrins, lightly mist all plant surfaces and the top of the soil. You don’t want the plants dripping wet, a thin mist will be enough. If there are fungus gnat larvae in the soil, spray the soil directly where adults typically rest to thoroughly moisten the top, then avoid overwatering. Let the soil dry to at least a 2″ depth. Reapply these in three to four weeks until the problem has subsided and the insects are gone.

A predatory mite of the Hypoaspis miles species preys upon adults and larvae. It also attacks other insects like thrips and springtails, which can be a nuisance in the garden or greenhouse. These are best employed outdoors or in greenhouses as single specimens are harder to treat.

So as you can see, there are many biological control agents to choose from when it comes to getting rid of fungus gnats. Apply insecticides in conjunction with good cultural practices and prevention methods and you’re set!