I love my Amaryllis but over the past few weeks I been having an ongoing battle with fungus gnats. These are the tiny little flies that appear out the soil around houseplants and seedlings evading any attempt to crush them. They are also known as Sciarid flies.  Apart from not being nice to have floating around plants, the small transparent or white larvae eat plant roots.

My go-to to solve this problem has always been a solution of hydrogen peroxide, 1 part 3% peroxide to 4 parts water.  This solution does not seem to affect plant growth but does kill off the gnat larvae in the soil. Several treatments are necessary to kill all hatching larvae but inevitably one or two flies seem to escape starting the cycle all over again.

Of course the ideal solution is to not get these little pests in the first place. Using sterilized potting soil is the best way to do that but if you have an integrated garden and greenhouse as I do these little nuisances find their way in. They are like a children’s colds. They keep coming around never to be completely eradicated but it is possible to keep them at bay or minimize their intrusion. Sticky yellow strips and other insect biological controls are frequently used in commercial greenhouse settings.

In come the Butterworts. My granddaughter, who also has an affinity to plants, sent me this picture of her new Butterwort.

I responded with, “ It has such a pretty flower and be careful it doesn’t eat you I up!”  as I knew Butterworts are carnivorous.

 “Exactly”, she told me “It will eat the fungus gnats”.  

 Apparently Butterworts are commonly used in greenhouses to help control the fungus gnats. They use them in my Granddaughter’s university greenhouses but I have not seen them yet in commercial greenhouses. This information I needed to check out as although I knew about other biological controls, I knew nothing about Butterworts effectiveness.

Butterworts, Pinguicula, like Sundew plants are carnivorous. Their hairy, glandular, leaves exude a sticky substance that attracts small insects with its smell. The leaves roll over insects and digest them utilizing the nutrients. There are both tropical and temperate loving Butterworts. They seem to all prefer a well-drained soil and lightly sunny conditions. As with all plants imitating their natural growing environment will likely produce the best results for happy growth.  

I have not yet acquired my new fungus gnat killer but I intend to and I will need to be careful to find ones best suit my indoor growing environment. It is certainly too cold yet for the greenhouse but a couple of temperate varieties placed amongst my soon to be planted seeds might be a real help.

If you have experience using carniverous plants for fungus gnat control, please respond with how effective you found them to be.