not specifically orchid pests...

[janet_a]

ok, i'm tired of the odd fungus gnat following me around the house. do sticky traps work for these?

and i'm tired of the fruit flies following me back from the kitchen at the office. sticky traps?? TIA...

[sunshine]

Why not give a try. The worst that can happen is they will still follow you around then get out the old fashioned fly swatter and give them a smack

[syndywindy]

whenever I have had fruit flies I set out a bowl or two of balsamic vinegar. You can add a small piece of old skinless fruit to it or a couple drops of dishwashing liquid if you want(you have to think like fly, what would you want for dinner?) Generally I just leave it out, the flies crawl in and drown. You can also put a piece of plastic wrap over the bowl and poke several small holes in it. Flies crwal in and can't get out. Fruit flies have a life span of 10 days and can reproduce quickly. Get rid of any old fruit, sanatize counters etc. As you can tell, I've had some experience with these critters and this seems to work the best. I replace the bowls with fresh vinegar daily until they are all gone.

[jay]

Try a carnivorous plant. I like Drosera (Sundews) or Pinguicula (Butterworts). There are a lot of places to find them online or at stores.

[11Orchid126]

A slice of fresh raw potato placed on top of the medium will draw them overnight. You will find them underneath. In the morning throw the potato out and put on a fresh one.

[solay]

All good suggestions. I'm starting to see them around the G/H lately and may have to do something before they get out of hand. Thanks.

[Ray]

Fungus gnats are attracted to sticky-traps, but one should take their presence as an indicator of a problem - decomposing potting medium. Think of them as the "canary in the coal mine" to warn of methane.

Fungus gnat larvae live off of fungus growing on decomposing organic matter. They will grow a large population, and if they outstrip the fungus, they will begin to devour roots.

Trapping the adults is treating the symptom, not the cause, so replacing the potting medium is the proper action. However, sometimes a population will be inadvertently carried over during repotting (it's tough to remove 100% of the old medium), and sometimes the plant is not ready to be repotted, so a drench in an insect growth regulator or insecticide that can kill eggs, larvae, and pupae is warranted.

[katrina]

Originally Posted by Ray

Fungus gnats are attracted to sticky-traps, but one should take their presence as an indicator of a problem - decomposing potting medium. Think of them as the "canary in the coal mine" to warn of methane.

I have to slightly disagree w/this statement. I used to be of this belief and thought it strictly meant decomposed medium (ie rotting roots) but in the past year+ time I've been experiencing a slightly different situation.

Keeping my masdies and bulbos very, very moist...seems to attract fungus gnats regardless of how new the medium is. I think they are first attracted to the moisture...even in new media.

I do agree though...if fungus gnats are out of control and the potting medium is aged...there could definitely be a problem that needs to be addressed. I just wouldn't over-generalize it by saying fungus gnats mean broken down medium.

Plus, when I used to grow Amaryllis, I used a peat based mix and brand new potting mix would be swarming w/fungus gnats w/in a couple of weeks. It's one of the main reasons I stopped growing those lovelies.

I hope that made sense.

Almost forgot...they larva love to first feed on root hairs and roots but they will also feed on organic matter in the mix... including the soils in terrestrial plants. The biggest worry over them (besides flying up your nose) is that they can transmit diseases. And, of course...we don't want our roots chewed and munched. :-)

If you know your medium is not breaking down (ie-it's new)...BT is a good solution....Bacillus thuringiensis. Getting rid of the larva is key to solving the problem.

[koshki]

Is BT in Bayer's 3in1? (Sorry, can't get to my bottle just now.) I ask cuz I just sprayed my masdies to control scale if found on a couple. But the flies are driving me mad.

[Brooke]

No Katherine, BT is the ingredient in mosquito dunks which kills the larvae of.....mosquitos but seriously, it also kills the larvae of fungus gnats too You can buy it at a big box store during the summer but I don't know about this time of year for us in the frozen north

It is easy to test to see if you have the gnat larvae. A raw potato slice inserted into the media will draw the larvae to gorge themselves. The larvae are the size of a grain of rice, easily visible. I used a frozen French Fry instead of a fresh potato. It only has to be inserted slightly into the media, wait 12 hours and if you have them, they will be there.

Any plant in your house with a peat based mix will be an invitation for them to set up shop. You can either bottom water or use sand or chicken grit on top of the container. The adult gnats will not burrow into a dry surface or a rough surface.

Switching from a peat mix to a coir mix will also stop them. For some reason a gnat does not like coir even when the coir is very moist, ala a hydro system for seed germinating and growing.

You can make your own yellow sticky cards with vaseline. Apple cider vinegar in a shallow container or wine, will attract them but why waste wine

Brooke

[PhalNewbie89]

Yes, we had some fly issues when we first moved in and we put up the sticky traps for your windows. We got all kinds of gnats and I didn't even know they were there.

[katrina]

You can also buy a powderd BT. You can probably find it at a hydro store. BUT, it's cheaper to just buy the dunks...which is what I did this year.

Katherine - if you can't find either...let me know. I have a couple extra dunks I could throw your way.

[Ray]

Kat, you're absolutely right that is does not necessarily mean decomposing medium, but that is probably the most common scenario. I hate when folks over-generalize, and you caught me doing it!

If you think about it though, the adults will likely only lay eggs in an environment in which their offspring will thrive, and that means fungus to eat. I suppose they might view a constantly moist environment as a "likely" one, but then again, a constantly-moist environment is more likely to germinate the fungus spores too, and I, for one, don't have any idea if the gnats are attracted to moisture or to something given off by fungus. Sounds like a "chicken or egg" thing to me.

By the way, BT is the bacterium Bacillus thuringiensis, and specifically the variety Israelensis is what is used for mosquitoes.

[katrina]

It's so funny that this is all opened up on 2 different thread.

Ray...correct you are! I always forget the "v." part of BT. Good catch!

And, yes, I agree...mama is going to lay her eggs in an environment that gives the offspring a strong chance of surviving...moist. As a matter of fact, I don't think they would even consider laying eggs in an environment that was anything BUT wet.

As for the food...primary food source is root hairs and roots...which can be found in brand new medium. They will also eat organic matter in the mix but that's secondary to those juicy roots.

[Izzie]

Lol, are you referring to mine, Kat? I kind of want to link this one to my anceps one.

[leeflea]

Janet, I might have misunderstood you but are you saying you don't want to use the sticky traps? Is that correct.
I had a problem with those pesky gnats and was so close to dipping all my orchids into an acephate solution! Even though I abhor the use of pesticides. Then I found some yellow sticky traps and I put them about the orchids and in about a week, I didn't see any more gnats. My experience with them is they worked for me. Lee

[leeflea]

Ray, good suggestion and education. I didn't think of decomposing media. Will keep that in mind should the little critter re-appear. Lee

[Izzie]

How much of a Mosquito Dunk would you use per gallon of water?

[janet_a]

my critter problems have actually mostly cleared up. the gnats seem to come in bunches; haven't had any fruit flies in a while.

now we got stink bugs.

[koshki]

I went ahead and sacrificed some wine, and positioned a sticky trap kind of half-way in the glass. There's been a noticeable decrease in the flies.

Thanks for the info about the potatoes. Turns out we had a stinker in the bag, and that might have been the beginning of the whole problem. It was out of my reach, and I had to wait for DH to help kick it out!