Fungus gnats and control

Rand Nicholson
Sat, 13 Dec 2003 04:32:18 PST
Yes, Mary Sue:

If you are going to try growing CP's (Carnivorous Plants) for bug 
control - beware! It can lead to a serious addiction. These weird and 
wonderful plants have a fascination all their own. Like many, I 
started by killing supermarket Venus Flytraps (Dionea muscipula) some 
thirty-five years ago and now have Nepenthes hanging in my living 
room window.

For Drosera: One of the best species to start with is D. capensis as 
it is easy, pretty (we CP'ers think) and tough as an old boot. Other 
Drosera may be a little fussier or a lot, especially the gemmae and 
tuber forming ones which have seasonal needs, although there are some 
that are almost as easy. This Drosera needs constant moisture (I grow 
mine in a pot sitting in about an inch of water), and are generally 
treated as bog plants. A mix of milled sphagnum peat and perlite at 
50/50, with a top dressing of live sphagnum moss is a good way to 

D. capensis has no noticeable dormancy period which makes it an 
excellent species to grow amongst plants on greenhouse benches and it 
seems to suck up fungus gnats and small flies like a vacuum cleaner. 
Of course, because of the nature of CP's, fungus gnats love to grow 
in their pots and CP's are, as a rule, extremely sensitive to 
chemicals and fertilizers will kill them outright.

For information go:

and click directly on the FAQ link. If you would like to see what the 
CP List is all about or browse through the archives, go:…

Hope this helps.

In The Great White North

>Dear All,
>I have used a product called Knock-Out Gnats sold by Gardens Alive! 
>that uses Bt. You have to use it in all your pots in that vicinity 
>and they recommend a soil drench for three weeks in a row to get 
>successive generations of larvae. It seemed to worked.
>As someone else mentioned a friend of mine said having insectivorous 
>plants in her greenhouse banished them as well. I ordered some 
>Drosera seeds from Silverhill but so far they haven't germinated. 
>Drosera is a geophyte. Does anyone on this list grow it?
>Mary Sue
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