Reply
Contributor
Posts: 63
Registered: ‎03-14-2010

Fruit flies in plants...help!

I bought a type of cactus from the Q about 4 years ago. Am so not a plant person. I have 2 black thumbs along with 8 black fingers. But thought I would give it a try. Only have to water this thing monthly. Love it! This should be the winter it blooms a white flower the size a a baseball that is suppose to be very fragrant. It has gone crazy growing this summer. Anyway, I will be bringing it back into the house when the air gets chilly and I alway have a problem with what appear to be fruit flies coming out of the soil and all over my apartment. I spray with some kind of pesticide and keep little bowls of stinky vinegar/dawn scattered around my apartment. Still have them. They do go away once winter kicks in but they make me crazy. I swore after last fall I was just going to toss the plants. I know they are in them again. Can anyone tell me what I can do about this. I live in a small town with no nursery to help me. Only a home depot and they can't tell me anything. Can anyone help me??? I really want to keep these plant!!! Ideas??????

Not applicable
Posts: 1
Registered: ‎09-21-2014

Re: Fruit flies in plants...help!

Bugs don't like garlic. You can make a garlic spray (directions can be found on line) or take a small amount of diced garlic & put it in the pot around the plant. Get rid of the bugs & won't harm humans or pets that may be near by.
Honored Contributor
Posts: 14,752
Registered: ‎03-15-2014

Re: Fruit flies in plants...help!

Fungus gnat larvae breed in damp potting soil. To get rid of them, make sure the soil completely dries out before watering again; the larvae will die in a dry environment. A cactus will be able to handle it. Also, watering once a month might be too much. Try watering once every two months. You can also put mosquito dunks in your watering can. Mosquito dunks contain Bti, a natural larvicide. The Bti will spread in your soil when you watering your plants.

Respected Contributor
Posts: 3,537
Registered: ‎03-15-2010

Re: Fruit flies in plants...help!

As Valu said, drying out the soil is key to resolving this problem.

This may be the time to re-pot the plant and make sure there is enough drainage.

Honored Contributor
Posts: 17,655
Registered: ‎03-09-2010

Re: Fruit flies in plants...help!

Fungus gnats is what I was going to write too about. One other solution is using the cactus soil and replanting the cactus. The gnats' larvae have difficulty going through the sand to get to the surface.

If its a regular houseplant in regular potting medium, I would add a layer of sand to the top of the soil to prevent the larvae from tunneling upward.

From the internet:

Step 1:Make the sand trap Collect all infected houseplants, and remove the top 2 inches of potting mix to dispose of the larvae already laid. Discard the soil immediately, and replace this top layer with sand, which is free of organic matter and dries out quickly—an unappealing medium for fungus-gnat eggs. Let the soil below dry out completely before the next watering. This should eliminate all fungus-gnat larvae present and prevent new eggs from being laid.

Step 2: Set up the open bar Adult fungus gnats are easy to lure and drown using any sweet liquid that smells of decay. A nice $2 bottle of alcohol-free wine from Trader Joe’s is one of the best and cheapest fungus-gnat baits I’ve found. Pour the liquid into a small saucer, and place it near a previously infected plant (or by all infected plants if the infestation is already rampant). If you let it sit overnight, then you should awake to a disturbingly satisfying collection of dead fungus gnats floating in the liquid. Discard and refill the saucers until the adult gnats no longer appear.

☼The best place to seek God is in a garden. You can dig for him there. GBShaw☼
Esteemed Contributor
Posts: 5,295
Registered: ‎06-06-2011

Re: Fruit flies in plants...help!

Our local master gardener suggests putting a layer of sand on top of the soil. Completely covering it. I believe he said about 1/2 "".

Women and cats will do as they please, and men and dogs should relax and get used to the idea-Robert A. Heinlein
Honored Contributor
Posts: 15,523
Registered: ‎09-01-2010

Re: Fruit flies in plants...help!

The best way to treat plants before bringing them inside, is to spray them liberally with soapy water. I have a huge Christmas cactus that spends 4 months of the summer on the front porch. Before I bring it back inside, I mix several drops of dish detergent in a spray bottle and cover every leaf, stem, and the dirt surface of the plant. I let this dry for a minimum of 4 hours before bringing the cactus inside for the fall and winter months. I've never had a problem with insects after treating my cactus.
Contributor
Posts: 63
Registered: ‎03-14-2010

Re: Fruit flies in plants...help!

Once again thank you, thank you for the ideas.