NewburyportNews.com, Newburyport, MA

January 22, 2014

Tim's Tips: Be on the lookout for fungus gnats

Tim's Tips
Tim Lamprey

---- — Often, a customer will come into the store and tell me about the problem that he or she is having with fruit flies in the home. He or she is puzzled because there wasn’t any overly ripe fruit in the house. The flies do tend to hang around the houseplants.

As it turns out, these flies are not fruit flies, they are fungus gnats.

Adult fungus gnats lay eggs in the soil of houseplants. The eggs hatch out, and the larvae damage the roots of the plants. Eventually, the larvae turn into adults and lay more eggs, and the whole cycle begins again.

The larvae can cause significant damage to the roots of your plants. Ultimately, enough damage can kill the plants.

Fungus gnats can be a major problem for a greenhouse that is growing plants and can be difficult to control. If you have plants that you put out each summer and then bring in again in the fall, you may be bringing the fungus gnats back into your home. Fungus gnats prefer a moist soil. If you have plants that you bring into the house and you keep the soil too wet, you will encourage the population of fungus gnats to grow.

Fungus gnats have become immune to many insecticides, but recent research has shown that there is an organic control that homeowners can use that is effective at getting fungus gnats under control.

Many of you have heard of a product called Mosquito Dunks. This product is used to control mosquito larvae in areas of standing water around the outside of your home. The dunks release bacteria that kill the mosquito larvae without harming birds and other wildlife. Scientists discovered that the bacterium that kills the mosquito larvae is also effective at controlling the fungus gnat larvae.

The dunks also come in a form called Mosquito Bits. The bits are granules that can be sprinkled outside in standing water. The bits can also be sprinkled onto the soil of your plants and then watered into the soil. Once the bacteria are in the soil, they attack the gnat larvae and kill them. This has proven to be the most effective way to control an infestation of fungus gnats on your plants.

If you have houseplants that you put outside for the summer or if you have brought a new plant into your home, look for signs of the tiny flies around your plants. If you see the flies, you should treat your plants with Mosquito Bits to get the problem under control.

Well, that’s all for this week. I’ll talk to you again next week.

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Tim Lamprey is the owner of Harbor Garden Center on Route 1 in Salisbury. His website is www.harborgardens.com. Do you have questions for Tim? Send them to ndn@newburyportnews.com, and he will answer them in upcoming columns.