Would someone please give me some advice on controling/eliminating fungus gnats? This is in 1/2 gallon tall palm seedling pots, in a greenhouse with artificial lighting. Everytime I seem to get rid of them they are back in a few days. I have tried systemic insecticide, sevin liquid, and pyrethins. These are pretty young palms, 3 to 6 months and I don't want to kill them instead of the gnats. Any advice would be appreciated.

           Thank you, Mike

Mike,

 The  best way to control fungus gnats is with a yellow, sticky trap.  The adult gnats are attracted to the color and become stuck on the paper card.  The card is about 4x6 inches in size.  Hang this on a plant stake above the foliage.  It takes about a week to control the pests. This is the best control, no chemicals, and no labor by the grower.

 The product I use is labeled as "sticky aphid whitefly trap".  These are available at retail nurseries or at www.seabrightlabs.com.

Thank you, I will try it. I realy appreciate the help.

Mike

Mike,

Sounds like to much moisture in your pots, Couple things you can do #1 us a soil mixture that drains well and won`t hold alot moisture. #2 If you do not want to change your present soil then use a form of fungus control the gnats are attracted to fungus. With this in mind you have fungus growing in your soil because of poor drainage. #3 This is some pesticides you can use for those gnats Deltamethrin spray, Talstar Liquid concentrate or something that contains Cypermethrin. Get rid of the fungus and the gnats will go away

Thanks for the advice Dave, you are correct about the soil holding too much moisture. I mixed up a batch that was too heavy on the peat and did not realize it untill it was too late. I am hoping not to have to repot them all as over 100 seedlings are involed. I thank you for your help, and I am sure I can get them under control with the suggestions I have been given.

           Thanks to both posters, Mike

Fungus gnats are endemic to greenhouses.  Just hold your nose.  You wont' be able to get rid of them, without harming your palm crop.

Bug killers, etc. seem to work, but they don't.

The only thing that really works, in my experience, is drying off between watering.

yeah, yeah, I know, they fly up the schnozzola, but who really cares?  I'd only worry if they're in your home or office.

dave

I use a light fungicide/insecticide/miticide treatment every 2 weeks weeks and this usually controls them without harming any of my seedlings. My greenhouse is 30'x60' with overhead irrigation. I don't think that I actually get rid of them but they are so low in population that I don't notice them. My treatment is broadcasted through the irrigation system using a cheap ($50) mixer. I also broadcast fertilizer and magnesium sulfate at the same time and knock-down a few birds with one stone. Prior to using the mixer, I used to squirt small amounts of palmolive dishsoap into the containers - before I had thousands of plants. This worked pretty good for the gnats and also served as wetting agent for the times that my soil dried out a little too much. Good luck!

So, did you get rid of them?

It's been a while . . .