Insecticide

Question:

I have a dracaena marginata plant. I had noticed small flying insects in my home, I thought they were maybe a fruit fly…found that the home for them was the dracaena ,,,can you help with the ridding of these pests?

Answer:

The flying insects are called fungus gnats. The larvae (eggs) live in the soil of plants near the surface. As they mature, they develop wings and then fly about. The winged adults live for only about a week before dying. The key is to eradicate the larvae living in the soil.

The gnat larvae require constantly damp soil and rotting roots in order to thrive. The presence of fungus gnats are often an indication of over watering and root rot.

First, scrape off and discard any loose soil from the surface of the rootball. This loose soil serves no useful purpose but it is where many of the larvae are located. Next, allow the soil of your Marginata to dry at least an inch deep into the pot or until the leaves start to wilt just s bit. By allowing the soil to dry deeper into the pot, you will deprive the gnat larvae of the moisture they need to survive.

Some folks have success sprinkling a very thin layer of sharp builders sand over the surface of the rootball. The sharp edges of the sand carve up the larvae as they move about. If you use sand, make the layer very thin. Very few of the liquid pesticides on the market are effective and they tend to keep the soil too moist, so I don’t recommend them or any other liquid home remedies.