January 6, 2016
People often ask me how I come up with topics for my column. Most of the time it is easy. If you get 3 to 6 people coming into the store with the same problem, then it must be a problem that a lot of people are experiencing at a given time. So lets go with that premise and we have this week’s column.
What’s with all the fruit flies in the house? Unless the bananas are going bad, those probably aren’t fruit flies. The flies are probably fungus gnats. They will look like fruit flies, but fungus gnats are black in color and they are a bit smaller than a fruit fly. The fungus gnats are coming from your houseplants. If you bought or received a new houseplant, or you had your houseplant outside for the summer, than the odds are that is where the fungus gnats originated. These little gnats lay eggs in the soil that eventually hatches out into larvae that live in the soil of your plant. Eventually the larvae develops into an adult gnat that then takes flight looking for a mate and a new place to lay eggs that hatch into a larvae and turns into an adult that looks for a new place to lay eggs… you get the picture. The fungus gnats can be a major problem in a greenhouse and unfortunately they are resistant to many chemicals. The adult gnat has one weakness and that is the color yellow. They are drawn to the color yellow. You can buy yellow sticky traps that you stick into your houseplant pots. The traps are coated with a sticky material that traps the gnats. If you can trap the adult gnats you will decrease the population.
There has also been a discovery that there is a bacterium that you sprinkle onto the top of the soil. The bacterium is watered into the soil and will then kill the larvae. By eliminating the larvae, you decrease the number of adults.
We carry the sticky traps and the bacterium in our store.
One thing that really encourages the growth of the fungus gnats is keeping the soil too wet. In the winter months, most houseplants are in their semi-dormant period. The plants don’t require as much water as they do in the summer months. If you allow the soil to dry a bit between the times you water, you will help to control the number of fungus gnats on your plants.
Well, that’s all for this week. I’ll talk to you again next week.