hi all, i re potted a lot of peace lilies for my neighbor but this year seems to be a bumper crop of 'gnats' for everyone here in eastern NC. her plants are a haven and her hubby is ready to ban the lilies...what can she spray/put on the top layer to kill the little buggers that won't hurt the lily. i've heard of white vinegar as a trap
but house plants aren't my forte.
thanks a bunch
First thing I would do is back off on the watering--I have never had problems with gnats unless I was watering too much and ultimately the overwatering will be worse for the plant than the gnats. You can put up yellow sticky traps to catch the adults, and use Bt (Bacillus thuringiensis) in the soil to kill the larvae. (Bt is found in things like mosquito dunks, and there also is a product called Gnatrol that has it as well). Most insecticide sprays should also take care of the adults, but you'll get rid of the problem faster if you also do something about the larvae.
You can use mosquito dunks in a watering can ... and there are other chemical remedies that provide relief, but the pest (best?) cure is prophylactic - stop providing a favorable environment by lightening up on the watering can, or adopt a soil that is better aerated - the plants will thank you, too.