Fungus gnats

Mon, 28 Mar 2011 13:57:38 PDT
Apparently M.A. Harris, W.A. Gardner and R.D. Oetting concluded in 'A review of the scientific literature on fungus gnats, 1996,' that a layer of sand did reduce the population of gnats though not by cutting them up.  Sand dries out quickly--which would depend upon the type of sand--and the gnats are confused, unable to detect fungus in the underlying medium, according to the few articles I found online on this subject.  Another study indicated that diatomaceous earth did not work because it absorbed moisture and cracked, allowing access to the mixture below.  I was unable to read either of these sources in their original form and found very little online addressing this issue.  As I indicated in my first post, my own completely unscientific experience is that it works.

I hear eye of newt boiled in the milk of a goat born on Walpurgisnacht
>works, but only if boiled in the light of a full moon.

However, unlike Dave, eye of newt has always failed me no matter how I prepare it, but garlic bulbs in every ninth pot (the placement is critical) is an effective deterrent and has the added benefit of warding off vampires with an undying craving for Scadoxus multiflorus. 

zone 8/9, Sierra foothills

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