Consensus on Orthene for fungus knats a NO NO ?

[Ray]

Orthene is often sold as a wettable powder or water dispersable granular form, so are meant to be mixed with water and used as a drench.

They add an odorant so you know to stay away from it, so use it outdoors.

[Cym Ladye]

Originally Posted by greenpassion

...... In looking it up I came across (in a bromelaide discussion board) someone expounding on the dangers of using orthene on orchids other than phals and various thick leaved plants. If this is so, what would be an alternative to using orthene?

The danger was in the carrier of the main ingredient, not the pesticide itself, when it was sold in liquid form. I have used the powder dissolved in water when needed on all my orchids for years with no ill effects. I have never used the granule form.

[NYCorchidman]

the presence of fungus gnat doesn't necessarily mean there's fungus nor the growing media is too old to a point that it needs repotting.
Fungus gnat larvae can feed on anything from fungi to wet wood (which many of our orchids are potted in).

They are usually just annoyance.

With regular potted plants, the mosquito dung drench works wonder, but haven't tried that with orchids. Orchids media do not stay wet enough for the bacteria to stay alive and do the work, or at least so I think.

I normally kill any flying adults that I find by just hands. Once I had the larvae killed in the regular house plants pot, I saw whole lot less. So if you have other plants that are planted in soil that stays moist pretty much all the time, then you want to treat the soil with the mosquito dung stuff and kill off the larvae. There are a lot more of them in the soil than you think as the adults constantly lay eggs while they are alive for one week or so. So breaking that cycle really keep the population down. plus kill all the adults everytime you find them like I do. If you have hard time chasing it and miss them, then try spray once and most of them cannot fly right away, then just squeese to death. hehehe

[got ants]

I am not sure, but I suspect applying Orthene to my Broughtonia species is what did it in. It was the soluble powder form.

I bought another plant, and have switched to Merit and it is still alive.

Coinkydink?

[silken]

Originally Posted by greenpassion

I have to respond to Ray's post in this matter. I am convinced that it's more than likely that the gnats are from the two orchids that I just received that are planted in moss/bark. I want to repot them, but they are both currently blooming. I want to wait until they are finished, then put them into S/H. As far as the suggestion of tape to catch the adults, my orchids are a center piece in my living area. I grow them on an island under track lighting, and this divides my kitchen from my living room. The idea of nasty tape being seen is not something I'd want to do. I'm going to look for Orthene. Do they make it water soluble-as an additive to the water I'd use to flush and water them?

I have used Malathion with great success to get rid of the adults and the larva. Granted it is stinky, but the smell will go away in a day or so. I spritz the air around the plant to drop the adults and then spritz the top of the media enough to wet it somewhat. That has usually been the end of them although you may want to spritz the media again in a week in case some eggs survived and hatched. But I think the Malathion would still be present in the media and kill any new hatchlings anyways.

[Leafmite]

Butterworts with round leaves are great at gettting rid of fungus gnats. I bought mine from an orchid vender.

[greenpassion]

You mentioned the powder form. Where did you get it? I can't seem to find it anywhere. I live in VT...

[Leafmite]

Many of these pesticides can be found in gardening catalogues or websites, especially nursuries that sell roses, fruit trees, etc. Roses and fruit trees require the big guns to grow.

[NYCorchidman]

Originally Posted by Leafmite

Butterworts with round leaves are great at gettting rid of fungus gnats. I bought mine from an orchid vender.

I would love to try these plants. I have venus fly trap and pitchers, but they are only good for much bigger bugs like houseflies and small bettles. It's amazing the variety of bugs I see in the apartment that come in through the open windows.

[james mickelso]

Repotting phals in bloom or spike doesn't affect the flowering or spiking as long as the roots aren't damaged. I have repotted some of mine in flower and it hasn't hurt them. Soapy water should take care of those adults that are hiding out in the moss. Put a little Bayers insecticide in it and that should take care of the larvae. A fungicide should take care of the fungus. Proper culture should take care of the fungus in the first place.