fungus gnats
 

could someone tell me how to deal with fungus gnats on orchids, i brought them in with another plant and did not know it, now i need to know how to get rid of them without doing damage to the orchids, thank you, donna
aswingsofeagles@sio.midco.net

Use Sticky yellow tape.. i got some from a local home and garden store... it catches the adults.. the larva are in the bark and when mature will fly up and also stick to this tape thus preventing further mating and egg laying

When was the last time you repotted?
Fungus gnats can be the result of deteriorated medium
and repotting with fresh medium can help to eliminated the problem.

Yeah,

And I dont know what type of orchid you're having problems with but these guys need moisture to survive.

I would repot like others have suggested and trim any roots that may have gone fungal. Hopefully they're just living in your substrate.

Good luck

A couple reasonably safe insecticides can be poured through the medium. One I use is Schultz brand Garden Safe Houseplant and Garden Insect Spray. It is 0.01% Pyrethrins and 1% canola oil. I suspect Neem Oil will work as well. That will nail the larvae which are teeny white worms. Like all the others have said, repot. If you have them in a Wardian case, this isn't really practical, thus the "insecticide" plus yellow sticky traps. If you do one or the other, that will eventually do the trick, however it takes much longer.

i have some small flies or gnats hovering around one of my den. they are just a bit bigger than fruit flies the stay over the one den primary but wander around the living room occasionally does this sound like the 'fungus flies' you have if so then i guess i found the thread on how to get rid of them if they sound like something else let me know please

on a more humorous note:
there hover over the medium of my den. thats doing the best so makes me wonder if there not 'good-job-thecanfield flies' ;)

OMG.. I have seen those! They are horrid but easy to kill. I simply let all the soil dry out for a month. Wouldn't try that with an orchid though ;) . They hate pyrethroid's. If you have those good old sprays with high concentration of pyrethroids spraying twice will eliminate them all once and for good.

Yes, fungus gnats. While the best medicine is prevention (repot the Den.) since it's doing so well you might opt for the double header (yellow sticky tags or old-fashioned fly paper for the adults, plus a safe insecticide for the drench.)

i hope you get this, i took care of the fungus gnats by putting one-fourth tsp physan 20 in a spray bottle with a quart of tepid water, sprayed the plants and "presto" they are gone, i only had to spray a little the second day and i do not see them around now, when these new ones hatch, i will have to spray again, but have broken the cycle and will get rid of them now, thank you, donna

I looked around a read a lot about these flys and about physan 20 and decided that it would be a good investment....then I couldn’t find any so I spent time reading labels and found Shultz Garden Safe brand Insect Killer and also the Fungicide both cam in spray bottle and were reasonably priced.
I went home a read the label toughly and then.....I sprayed my whole plant table and as advertised the little buggers (hehehe) died, I had little black dots all over my table after that day everyone in a while when I would see one or two flying around I give a little shot of the spray to that area
Now it’s been a couple days and ive sprayed the fungicide over my plants to hopefully keep any fungus away.
ThanX for all the help.

i visited with an orchid grower that knows what she is doing, she told me to get green light spray for fruit trees, which i have ordered, found it on amazon.com, the place where they sell books, it is concentrate and you mix it with water, she said to put it in your water when you water the orchids and it takes care of the nymphs, i also being desperate bought a gnat dip to take care of the ones in the dirt but you can do this with the green light junk too, my problem stemmed from that fact that i am a novice and just learning about orchids although i have a lot of them, when i got them i repotted all of them in miracle grow for orchids, that was perfect medium for these darn gnats, so now i am the process of repotting everything in small lava rock and long fiber spaghnum moss, i soak both the rocks and moss in water for about an hour, put a few rocks in the bottom, wrap the moss around the base of the plant, put it on top of the rocks and then fill in around the sides with rock, covering the top of the moss, i didnt want to get six months down the road and have my plants worse off than they were, she told me to regularly treat my plants by putting a fungicide in the water to keep fungus and other things away, so that is what i am doing also, orchids are complicated and i am learning fast, but oh how beautiful they are, glad to have helped, happy orchiding to you-----lol, donna