OH NO!!! Fungus Gnat problem - Orchid Board

Country Gramma · #1 11-23-2009, 09:49 PM

Hi, I hope someone can help. I saw a bug crawing around the roots of a Phal and another on a Mtda. Maui Charm that I got at the orchid show in RI Fri.

I also got some Sticky Stakes

there and promptly put them out. Caught a Fungus Gnat and now I need to treat. Any help????

Thanks, Karen

Blueszz · #2 11-24-2009, 10:14 AM

A lot of bugs that live around the roots will come out of the pots when you dunk the pots for a few minutes. They can't breath and will come to the surface. If you do this a few times (with each watering) you might get rid of the bugs without pesticides.
About the fungus gnat. Don't worry too much, they only cause problems when you have loads of larvae in the medium. A way to get rid of these is keeping the medium a little dryer - or let it dry out between waterings 1 or 2 times...

Nicole

Undergrounder · #3 11-24-2009, 11:18 AM

Adding a bit of hydrogen peroxide to the water is always a good way to kill off soft-bodied bugs, if you do the dunking thing, add a little H202 to the dunking water to give them a little extra 'motivation' to leave your orchids alone.

Royal · #4 11-24-2009, 11:42 AM

Where there is one, there are more. Letting the media dry more rapidly will help. No fungus, no fungus gnats. No gnats, no larvae. ONE larva can ruin an entire spike. I would take no prisoners.

BikerDoc5968 · #5 11-24-2009, 12:31 PM

Bayer 3-in-1 Insect, Disease & Mite Control contains Imidacloprid: 0.47%; Tau-fluvalinate: 0.61%; Tebuconazole: 0.65%. The 1st listed is used for grubs or the larvae. The other listed ingredients are antifungal/bacterial. Also, any of the Permethrin containing products will kill the flying gnats. As Royal said, "Take no prisoners!"

Donald · #6 11-24-2009, 12:56 PM

You could also consider GNATROL.

OrchidSue · #7 11-24-2009, 01:34 PM

I tend to get fungus gnats in the winter, so this year got a couple of carnivorous plants (Drosera). The D. capenensis is a champion fungus gnat catcher

. Butterworts are also excellent. These plants are really cool on top of everything else. They do tend to to need lots of water, NO fertilizer, and good humidity.

Susan

Donald · #8 11-24-2009, 01:43 PM

I am thinking that the carnivorous plants could only survive happily under some fairly high humidity conditions or I'd be willing to give them a try just for the enjoyment of them.

OrchidSue · #9 11-24-2009, 01:52 PM

Quote:

Originally Posted by Donald

I am thinking that the carnivorous plants could only survive happily under some fairly high humidity conditions or I'd be willing to give them a try just for the enjoyment of them.

When I bought mine, I asked about the humidity and they said if my orchids were doing fine, then the Drosera would be fine. I grow them in amongst the orchids under T5 fluorescents and they seem to be doing great. So far I haven't even had to keep them sitting in water-I just water about every 2-3 days. I am lucky that Seattle has great water and can use that. Otherwise, you need to use distilled or RO water.

Susan

Ross · #10 11-24-2009, 01:58 PM

It was barely mentioned, but gnats aren't really the problem - they are the symptom or result of the problem: decomposed medium. If the rooting medium is fresh (or not rotten) there won't be fungus for the gnats. Yellow sticky traps or Butterworts work just fine for the adults and sprays work fine for the wire-like grubs (nearly invisible) but they'll come back if the medium is too decomposed. I recommend taking care of the basic problem first. No food - no bugs.