Fungus gnats and control
Rodger Whitlock (Sun, 14 Dec 2003 09:27:50 PST)
On 11 Dec 03 at 15:57, David Fenwick wrote:
I once drenched pots with malathion for the fly, and all of them
came to the surface coughing. I thought right I can blast them with
something else now and used an aerosol, a household flea and fly
spray containing pyrethrin. Boy it was good control and really
successful for the fly. Sadly all the seedlings died as well, it
would seem that the plants were phytotoxic to the butane propellant.
The death of your seedlings is more likely due to the malathion than
the butane. Malathion is known to be phytotoxic to some plant groups
and the label will say "do not apply to X, Y, and Z."
Butane itself is a very simple compound with very little
physiological effect to be expected other than possibly displacing
air temporarily.
Other possible culprits include the pyrethrins themselves and the
vehicle they are dissolved in.
--
Rodger Whitlock
Victoria, British Columbia, Canada
Maritime Zone 8, a cool Mediterranean climate
on beautiful Vancouver Island