Disinfecting seeds
Rodger Whitlock (Sun, 14 Dec 2003 07:21:39 PST)
On 11 Dec 03 at 10:41, Jamie wrote:
Another problem I have, and perhaps some of you have methods to
combat it, it fungus flies (or similar). They lay their eggs in the
medium and the nematode-like larvae eat the seeds! I've tried Neem
and insecticides that are on the European market watered in, but
without real effect. Sterilizing the earth is not the answer as the
flies could care less! Anyone have a good method?
Two things come to my mind.
One: You need to clean up your growing area. It was one of the
great advances in human understanding when it was realized that there
is no such thing as spontaneous generation of organisms; those fungus
gnats are coming from somewhere, most likely your other potted
plants. Get rid of the infestations in those and your seed pots will
not become infested in turn.
If it's impossible to clean them out entirely, try screening your
seed pots with fly screen, cheesecloth, or something like that.
Two: Perhaps your seed mixes are too peat-rich. Traditional
horticultural lore associates fungus gnats with peaty potting mixes.
This may be complete b.s.
I have a number of ordinary large-flowered hippeastrums that have to
overwinter in the house, and fungus gnats sometimes become a
nuisance. I have found that an ordinary pyrethrin-based household
insecticide spray does a good job of controlling them. If you spray
about once a week, being sure to get at the soil surface, their
numbers decline very rapidly.
Pasteurization of the growing medium before sowing is, of course,
essential in order to destroy any fungus gnats in it.
--
Rodger Whitlock
Victoria, British Columbia, Canada
Maritime Zone 8, a cool Mediterranean climate
on beautiful Vancouver Island