Bayer's tree and shrub is the opposite of what everyone was suggesting. It is a systemic insecticide, which means it is taken up into the plant's cells, and makes the plant poisonous to sucking insects. It does nothing to kill larvae in the soil. Gnatrol and other BT controls kill gnat larvae in the soil, and is toxic to nothing else but insect larvae.

Bayer T & Sis not meant for indoor use, nor for potted plants, though some people do use it that way. I've used it to eliminate a mealy bug outbreak. No doubt The Chemical Crusader (aka Rhizo) will be along to scold me shortly.

My suggestion is Knock-out Gnats, a BT control from Gardens Alive. It seems to be more readily availabe in cheaper, smaller quantities than Gnatrol, and I know it is effective. (I have no affiliation with the company or product)

Here is a link that might be useful: Knock out gnats

Will it harm the plant if I use both? I have some hoyas and while I think their not infested with mealies yet, I know their prone to it. I would like to prevent them from ever getting them or other insects, wich is where the BTS will come in handy. I've tried Garden Safe insect spray, and it has worked well. I would have to keep using it if I don't want them to come back unlike BTS wich you use once a year. I had a hoya rope that couldn't be saved. I had to get rid of her. If I had used BTS in the beginning it would have prevented the infestation.

Forgot to add this. I read mosquito dunks are also an alternative and also cheaper. I did some research here about that but didn't find exactly how much I should use per gallon. I have all my plants potted in 4' to 12' containers. Just wanna know my options and then i'll choose wich one I wanna try first. Kinda wanna try this one first since is more economical.

Bayer's product is NOT (as in NOT) to be used for indoor plants. Period. There are also no directions on the label for container use because it is not intended to be used on container plants. The reasons for those obvious omissions are stunningly simple. Any use of their product that is glaringly against label instructions may be unsafe for YOU and/or unsafe for your plant. Imidacloprid (the active ingredient) is a very hazardous product. You don't want it in your home for months and months to come.

If you have further questions about this, you should call the 800 number that you will find on the label. If you don't have a lot of insect pests on your outdoor trees and shrubs, perhaps you could return this product and find some Gnatrol.

I forget who it is in this forum that has used the mosquito dunks as the source for Bt-i. Unfortunately there are no directions for that, either. ;-) Perhaps whoever that is will chime in with her 'recipe'. Personally, I tend to use the product that is manufactured or processed for the intended use. It almost ALWAYS ends up being a great deal more effective, efficient, and economical in the long run. For example, the package of mosquito dunks may be less expensive than a bottle of Gnatrol, but how many gallons of water will they treat?

There is, actually, instructions on the label for container use, *BUT* it is only recommended for outdoor use, as Rhizo indicated.

I'd read on another forum that a couple of people use the mosquito dunks (they come on a 'card' and they're a 'donut shaped' thingy, for lack of a better word!) to rid their plants of gnats with much success. One person said she dissolves about 1/4 of the 'donut' in a gallon of water.

I've recently seen those at our nearby WalMart and hardware stores.

I called the number in the back of the bottle. They said BTS will not do anything for gnats or their larvae. I'm going to return it today, as i bought it yesterday and still have the receipt. Nanw, i read somewhere here about using 1/4 of the tablet per 2 gallons not 1, perhaps someone that has used it with great sucess will come forward. Rhizo, theirs 6 tablets per packege, so if you use 1/4 per gallon or 2, it will last for a long time. I believe you use it once or twice a month.

Thanks, nanw....I try to keep up with the labeling on the 'chemical du jour'! ;-) I've reviewed their on-line label to no avail (pertaining to containers) so while out running errands today, I looked at the fold-out label on a bottle of this stuff. Again, if we are talking about the same stuff, Bayer's Tree and Shrub systemic insecticide, I did not see any directions regarding the safe use for containers.

Is there another Bayer product that you might be referring to?

Here is a link that might be useful: Click here, then download product label

I use the mosquito dunks, with success, its about 18$ for 10 of them and about one forth of one will work if you soak overnight in a gallon.

I initially found GW because I was researching fungus gnats on the internet...so I have to say, there is at least one good thing about fungus gnats! Just kidding...I love GW, but there is NOTHING good about fungus gnats.

Anyway! I did not buy mosquito dunks because the only place near me I could find them was ebay. I read a post on GW which recommended first, to STOP WATERING and then to coat the top of the soil with about a quarter inch of coarse sand. THIS WORKED! My only regret is that I completely repotted one of my larger plants before trying the sand technique with another. I basically sacrificed a whole growing season's worth of new growth on the plant I repotted, while the infested plant that got sand on top grew and thrived and is now gnat free. Try it. It might work for you, too!

-Sarah

Reducing watering definately works. Never tried the sand method. I'm a lazy waterer so I've never had fungus gnats at home. At work I'd just toss the plant, wasn't worth it to deal with them. Sometimes my girls overwatered....

Mosquito Dunks should be available at Home Depot for about $12.

The only way I ever got fungus gnats was from packaged soil that I bought and used without checking it first, or amending it with perlite. And boy did I ever regret it once my plants were already repotted, and I thought they were fine, until I got up really close to them, which I do with some regularity (!), and bugs flew in my face! You've got to be careful about buying potting soil, I know that now.

I've tried reducing water and for me that totally does not work (atleast for me). I still see them flying around, almost waiting until I do water so they can jump in there. Yesterday I returned the bayer's and got mosquito dunks, they were 6 for $8.50. I didn't find any yellow sticky tape. I went to walmart, hd and lowes. I guess a lot of ppl are having problems with flies. I'll keep you guys posted. Changing the subject, does anyone own a gynura 'purple passion'? sometimes mine get their leaves all soft and floppy. I'm not sure why this happens. The rest of the leaves are nice and firm. I've tried give in it more sun or more water. I know they like to be on the dry side so I don't put to much water in it. Once their limp like that, they don't seem to get better so I have to cut the leaf. Anyone had this problem?

One more "tool" you can use in your fight against gnats are carnivorous plants like Ping/butterwort/pinguicula they're like living sticky tape.

As Ralph Snodsmith ALWAYS says "Read the lable!"

Tom

You can purchase sticky traps at www.gardensalive.com They had a big sale..20.00 of your first purchase..
Smith, try running a fan in the room where you have gnats and be sure soil dries between watering..Dry, stale, no-circulating air invites these bugs. Skip the insecticies, and infest in a rotating fan..they can be used in winter, too..Also, a humidifer would help. Gnats love dry air. Toni

Let's remember that Bt is NOT a chemical insecticide. If the infestation of fungus gnats is acute, then all the fans in the world will not do much to help. That's when a Bt product would put an effective and efficient stop to the problem.

Toni, dry air has nothing to do with an outbreak of fungus gnats, which thrive in humid, moist conditions. As a matter of fact, I can't think of ANY gnat that thrives in dry air. Drying the environment (soil, air) will slow down an outbreak of these pesky critters.