Fruit Flies infesting my plants?!?!

i've developed what lookto be fruit flies all over my house plants.
they are multiplying, despite my spraying insectisidal soap, and putting all the plants outside for 2 weeks.
ugh. i keep smooshing them, don't know what else to do.
anyone else ever get these and what do i do? stephanie

i searched other threads and found this:

http://www.everything2.com/index.pl?node_id=1388265

so i'm going to try it.

I agree, fungus gnats were the first thing that came to mind for me when I read your first post. I've had them on occasion but never had serious damage to the plants from them, I know the website tells you they can do damage to the plants and I'm sure they can, but to me they're a sign of a bigger problem which is that you may be overwatering your plants, and that'll probably kill them faster than the gnats would. Every time I've had them it was because I was watering something too much. So in addition to doing whatever you want to take care of the gnats, I would check on your watering.

That is a great link. I have this problem right now with my H. multiflora, which likes to be kept on the moist side so it is hard to let it dry out. I used the sticky cards and the gnats are really covering them. I think that I will try the hydrogen peroxide method. I'm also wondering if BATS will kill them. Does anyone know?

I was plagued with fungus gnats a couple of years ago and just couldn't get rid of them. Come summer, I put all the plants outdoors. Before bringing them in I sprayed each one with insecticidal soap while it was in an inverted tomatoe cage, then covered all with a garbage bag.

Clean is the key word. All ornamental containers were scrubbed and dried thoroughly. The plant pots should be washed off too, and any dead or decaying leaves removed.

Some people give the plants and all a good hosing down, which is a tremendous help.

No problems last year. I did see the odd one but quickly got after them with bug household bug spray.

Get a lizard. :)

A DGer from the AV forum made a great suggestion to me... mix up some dog flea and tick shampoo in a gallon of water and pour through the soil. Let me see if I can find the ratio...

Here ya go... there's alot of good info from people here...

http://davesgarden.com/community/forums/t/760314/

Lizard is more fun. :)

The fungus gnats lay their eggs in your too damp soil, then the larvae live there till they "grow up"....If you go to your garden center or hardware store or anywhere they sell garden pond accessories, you should be able to find those tablets that you put in any standing water (ponds, birdbaths etc) they release some sort of biological ingredient that kills mosquito larvae when they eat it, and it also works on fungus gnat larvae. Drop about a quarter tablet into a gallon of water, let it soak overnight, then water with it. This method may take a few weeks and will have to be repeated to get all the generations of larvae, but it is safe, not a dangerous chemical, which is obvious because it will not harm fish, frogs, turtles or birds that visit garden ponds.

To bring more immediate relief, try watering the top inch or so of soil with hot tap water, this also kills some of the larvae and adult gnats. I read about doing this on a tropical plant forum, not sure which one though. You don't want to use boiling water, just hot water, like the temp it is just when you no longer feel comfortable holding your hands under it. I would NOT do this with very delicate plants, though, and be careful not to soak the whole pot. In fact, water this way at your own risk...it has worked for me, but I don't grow real delicate or sensitive plants, so you need to decide if it is the right thing to do for the type of plants you grow.

Good Luck!

Ever wonder where these beasts come from? Today, I opened a brand new sealed bag of Miracle Gro potting soil and out flew hundreds of them. I would return the bag but couldn't remember where it was purchased. Hate to think I spent good money to buy fungus knats. I dumped the bag full in the compost heap where I hope they will freeze this winter.

Eeewwww!!!

they are pretty disgusting. i put out a strip of fly paper and caught over 60 last night, icky. also i'm using the hydrogen peroxide method. they seem to be getting less and less, just have to keep it up until they are gone. i had a client over last night and one kept flying around my face. i was so embarrassed, and explained my issue.
ugh.

I'm laughing but it's not funny.

makshi......lol!

I probably have about 60 on my yellow sticky traps as well. Tomorrow night I'm going to try the peroxide method too. I hope it works. The only other time I had a bad infestation was when I was growing Streptocarpus, which you always grow kind of moist. I finally threw out all of the plants and did away with the problem. I don't want to go that route this time.

The peroxide method seems to be working or at least it didn't hurt the plant at all. I could here it fizzing, and I hope it was burning those little nymphs to death.

I agree...that peroxide method does seem very good. Cheap, non-toxic and effective. Certainly worth a try. Amused by your last statement Hoya_24.

I'm not really a violent person, but anything that interferes with the enjoyment of my plants makes me mad.

i just got rid of a houseful of fruit flies after battling with them for years!!! Just make a paper funnel, tape the edge after placing it in a glass with a little apple cider vinegar and a drop of dish liquid. dont let the liquid touch the funnel. put several glasses around the problem areas. I swear to god. it was the answer. funnel is key. they can't get back out and over a few days, there were none left for the first time in ages!!! good luck.

Me too, Hoya. With those varmints, I could care less.

Soulja...you are talking about fruit flies and not fungus knats, right? My neighbor has lots of apple trees and lets the fruit rot on the ground breeding fruit flies by the thousands. Every year they are such a nuisance to put it mildly.

then you'd need lotsa little glasses i guess... HA! yeah, fruit flies, but I'm talkin indoors, though i imagine it could help outside. the vinegar seems like candy for them, the dish soap makes their little feet stick & drowns them, and the funnel keeps them from getting back out and from feeding on the edge of the glass. also, covering all drains in the house is important because it's their dinner table. BAM! gone. i couldn't believe it.

The fruit flies do come in from outside and I hate them. I will try your vinegar and funnel trick on them this fall. Thanks for the tip!

Buy mosquito dunks and put them into your watering can. That will get rid of the fungus gnats.

Thanks andidandi for that suggestion. Are they expensive?

Nope. About $10 for a package that will last you a lifetime. In the pool supply section. Here is an earlier thread that may be useful for you to read over:

http://davesgarden.com/community/forums/t/583366/

Interesting andi..

I did a quick search and found this. I see the mosquito dunks are a biological control and completely harmless except to the larvae. Now the next question. I wonder how much of a piece to put in say a 1 gallon jug or to make it easier, a five gallon bucket?

http://www.planetnatural.com/site/mosquito-dunks.html

Enough of a piece that it doesn't fall out in the watering spout. For me, that's about a quarter of one dunk. I just put it in there and forget about it until it dissolves completely after several waterings and is no longer visible. If you have a real problem, leave the water in the can overnight.

This message was edited Sep 8, 2007 11:58 PM

LOOK at this! Miracle Gro admits it themself that their soils may be infested with fungus knats.

Quote:

Insects

"Miracle-Gro® potting soil is a natural product. We do not sterilize the soil nor do we claim to on the package. In some rare cases, potting mixes can become infested with fungus gnats. Fungus gnats enter the bagged product through the tiny air holes in the bag that are necessary for the soil to "breath". Fungus gnats are often mistaken for fruit flies. They do little damage but are unpleasant if present in large numbers. Allowing the soil to dry out between watering will help control them. "

http://www.miraclegro.ca/faq/

I have never seen fungus knats in pure peat mixes only ones that have ingredients like "compost" or "forest products". Has anyone opened a bag of so called potting soil and thought you had just opened a bag of mulch?

Snowrose, the mosquito dunks really work...they come as round discs, I break off about a quarter of a disc to soak in a gallon of water overnight. Of course, now I am thinking about trying the hydrogen peroxide method.

As for Miracle Gro, I sent them an email earlier this year about the amazing amount of insect life I got in one of their bags of soil. They were not very helpful, they gave me a lesson on what fungus gnats were, as if I needed it, and that was about it, and also said that they know they are in their products at times. Alot of the insects must have been in egg or larvae form at the time I bought the soil, and only showed up later...but I had to repot everything I had in that soil. It was disgusting. Of course you expect a certain amount of critters, but this was way beyond acceptable! Yuk! Never again will I buy their soil for any reason.

Good morning, Bhavana. I think I will get some of those mosquito dunks to have on hand and peroxide.

As far as MG goes, to me their potting soil product has changed from what it used to be. I remember it as fuffy and nice. Now it is too much like mulch, at least the last couple of bags and the fungus knats were hideous in the most recent one. The thing is, Sterns has overrun the market and it is more difficult now to find other good quality soil mixes. For my violets and other gesneriads, I make my own mix from pure Canadian sphagnum, perlite and vermiculite. No problems with that.

Snowrose, that is what I do for the most part now too, and you are right about their soil being very "mulchy." I buy Shultzes African Violet soil, orchid bark, and perlite in big bags....most of my schlums, epi types, hoyas and rhips and other tropicals get a mix of soil, bark and perlite - with a little less soil for hoyas and epis. AV's get mostly the AV soil with a little more perlite mixed in.

When it comes to the hoyas or any epiphytic plant, I love to water and see it come gushing right out of the bottom of the pot one second later, telling me the drainage is very good. I have to feed a little more due to the small amount of soil I actually use, but it is worth the extra hassle not to worry about any root rot.

Whatever problems people may have with MG, what I've found is that the rival brands have incredible amounts of weeds in them. I bought two other brands when my local store was out of MG and every time I water I have to pull weeds from the potted plants. That's a mistake I won't make again.

I agree, andi. I had some Schulz potting mix that produced lots of some type of weedy grass that was awful to try and pull out.

Both would be a pain in the neck for sure, but I will take the weeds over bugs anyday!!!

I too keep a piece of mosquito dunk(Bt) in my watering can. I had a terrible infestation of fungus knats last winter. They even infested my terrarium. I finally thought of the mosquito dunks which I keep here all the time. Started using them in my watering can and eventually no more problem. They would have been gone faster if I'd used sticky traps to catch the adults along with the Bt in the water for the larvae.

Lana

It was getting pretty late in the season to find Mosquito Dunks so I ordered them on line. In case any one is looking for them, they are available at That Pet Place.Com
The prices are: 2 for $5.99, 6 for $9.99, and 20 for $16.89, I bought the 20 pack, which should last me for years. I ordered from them, because I have been ordering aquarium supplies from this vendor for over 15 years.