A friend emailed me asking for information on controlling gnats in her AV. I am not really sure what she is asking about as I have never had such a problem. She says she was advised to use Gnatrol or Knock Out but prefers not to.
One person has told her to use Murphy's Oil Soap at 1/2 cap per gallon of water; but another person advise this is not a good idea as it would alter the ph of the soil.
Can any one enlighten as to what "gnats on violets" would be and how to control them?
This message was edited Feb 22, 2010 12:07 AM
Gnats in violets
After doing a little more research I realize I have had these occasionally. Am I correct that they also are what are sometimes called fruit flies?
I still am open to suggestions for organically controlling this little pest.
The are called fungus gnats and I've had them off and on for years but they are worst when the soil is damp for very long periods so letting things dry out a bit is a good method. But they can still exist even if you do that. I am not sure why your friend doesn't want to use Gnatrol it's a natural control that is very safe to use and is most likely considered organic though I'm not sure. It's made with a from of bt - not all bt work the same way as I understand it so you have to make sure you get the one that kills mosquitoes as it also kills the fungus gnats. Oh and they are not the same as fruit flies but look very similar I think.
She can also buy the yellow sticky traps for the adults. Diatomaceous(sp?) Earth can be mixed into the soil to kill the larvae.
Shanika is so right!! A soapy water spray will usually control them too,unless they are out of hand.The good thing is they are not nearly as harmful to your plants as pests like mites or mealies.They are just unsightly.Diatomaceous(sp?) Earth is also organic.
Lynn
One quarter of a "Mosquito dunk" will help kill the larvae in the soil. Sticky traps for the adults.
One quarter of the dunk goes in your watering can. Forgot to mention that!
gnats are attracted to damp soil, that has rotting vegetation - such as leaves, dropped blooms, etc. Lynn is right - they are a nuisance, but not really harmful to the plants (just a pest). If your friend wants a non-chemical treatment, then the yellow sticky strips work great.
Thanks every one. I am passing along this information, seems her club is trying to resolve the issue.
I've used the Murphy's oil soap, doesn't get rid of every one but does knock them back significantly. But the ratio is ONE capful per gallon of water. I would think that top-watering once or twice after the problem is resolved would rinse away any residual stuff.
I've never had them do actual harm, but I've heard that if they're present in large enough numbers, the larvae can damage roots, especially on young seedlings or developing plantlets.
Whoa, I fought the durn gnats for almost a whole year; the yellow sticky tapes cut in smaller pieces layed on the pot soil and letting plants get a little dryer worked over time. Boy, I hated those SO bad. Hang in there, you will eventually get rid of them if you perservere! ChuLin