How do you kill the gnats in your potted palms?

[Justin]

I'm referring to the tiny fungus gnats that sometimes get into potting soil, as must have happened in my case. Short of repotting (which I would much rather not do because of the pot size), what is the best route for eradicating these little buggers?

[Cristóbal]

If the palms are outside of the house let the soil dry completely 100% 2-3 times. The dry soil kills the fungus gnats they need wet soils. If the palms are in the house and you cant put them outside theres some control biological for them it is called bacillus thuringiensis you can buy on the internet.

I use this control in my house with 10 palms in pots about 5 years ago for many hundreds of fungus gnats. It is very good and eliminate all in one month.

Edited February 14, 2010 by Cristóbal

[BS Man about Palms]

Either you need air movement or less moisture.

[Kathryn]

Adding coffee grounds seemed to work for me.

[Moose]

Adding coffee grounds seemed to work for me.

Thanks Kathryn - I get the same results using your suggestion!

Organic fertilizers seem to attract them.

[XYZ]

Justin:

Having had to deal with fungus gnats on a regular basis due to the type and moisture of media I use for some very delicate rainforest tree seeds that I work with, I strongly recommend Enstar (S-Kinoprene). It is a somewhat costly but extremely effective biorational that is also good for armored scales and so forth. I drench soils at a rate of 3 cc x 3.8 lt = 3/4 tsp x gl every week or so for three applications and they're done. If you're impatient for instant results, mix 5 cc = 1 tsp. of malathion into the drench first time out the gate.

I have used BT pvs in the past for fungus gnats but I have not found it terribly reliable in terms of 100% control when you must maintain perhumid soils.

Enstar is sold online at Hummert Intnl....alternately your friendly neighborhood ag-chem supplier may stock it. Purchase the smallest presentation available, it should last you quite a while.

BRgds,

Jay

[Mark_NoVA]

A couple more options:

Knock-Out Gnats works

Bayer shrub/tree seems to work as well, although I don't think it's advertised as such. I had a fungus-gnat problem this year, and they disappeared immediately after I used the Bayer. I had also applied some 2/3-year old Knock-Out Gnats a couple of weeks before, but it appeared to have lost its usefulness by then.

Yellow sticky-traps can help, but don't seem to cure the problem.

[Rafael]

CAN ANYONE UPLOAD A DEMONSTRATIVE PIC OF THIS PROBLEM?

Edited February 18, 2010 by rafael

[daxin]

One biological control is a small carnivorous plant called Butterwort(Pinguicula moranensis and other species). It is nature's more effective version of yellow sticky card. It likes warm moist shade and is very easy to care for. There are even nice magenta flowers during the warm months. I was very happy to see a significant drop of fungus gnat population in my greenhouse and all the kills were clearly on display. If this is for a highly visible area, I'd recommend spraying off the dead bugs once in a while.

[OverGrown]

I use Neem Oil for most problems.