Answers Posting - Damping Off problems

Nobody nobody at hgmp.mrc.ac.uk
Fri Aug 4 04:05:43 EST 2000


Hi All,

Thanks for the many responses to my problem.  Since some people
mentioned that they also had problems, I'm listing a summary of the
suggestions.

1.  Steam sterilise or Autoclave the soil (hasn't always prevented it in
our hands)
2.  Sow in small pots rather than big flats to minimise the losses if a
local infection does spread out
3.  Limit the amount of dead biomass standing around..so spray with
Basta early rather than late - as soon as cotyledons open (D Marks),
followed by a spray a weak later to exterminate late germinators.
4.  One suggestion similar to 3 was to presoak the soil in BASTA
solution (92 mg/litre) and sow on this so you get immediate selection
post germination.  I haven't found BASTA selection effective when we sub
irrigate with it on our soil mix, but will try this and see if it works
for us
5.  Some people include fungicides with the Basta solution - Steve
Jacobsen mentions Daconil.."Its a multipurpose fungicide that works well
for us.  Its sold in the
states by Ortho over the counter.  Active ingredient is Chlorothalanil
(tetrachloroisophthalonitrile) 29.6 %.  We put about 5 mls of this stuff

per 4 liters of water and use this to initially wet the soil.  We put in

enough of this that the plants are in standing water for the first 1.5
weeks of their life".  Susanne Kohalmi mentions "We have switched our
sterilization method using a compound called PPM (Plant
Preservative Mixture) purchased from Plant Cell Technology. According to
the
description it is a broad based anti-fungicide."1 part PPM, 9 parts
sterile ddH20. Immerse seeds in sterilization solution overnight (8-12
hours) followed by planting seeds directly                     (there
appears to be no need to rinse). I germinate on culture media (0.5xBM)
and transfer to soil at a later point in development.
>From Karin Koehl (Koehl at mpimp-golm.mpg.de)
Bernd Mueller-Roeber forwarded your message about your damping off
problems
to me. We sow 1000s of Arabidopsis seeds each year but hardly ever have
had
damping off problems. As a preventive measure, we soak the soil with a
solution of the fungzide Previcur N (0.15 % Previcur solution
(propamocarb-hydrochlorid 722 g/l, AgrEvo) one day before we sow seeds
or
transfer seedlings. Please check yourself whether the use of this
fungizide
is permitted in the UK. I hope our method will help you.

Kind regards

Karin K=F6hl

6.  One person (Gijs van Rooijen <vanrooij at ucalgary.ca>) preselects on
agar plates containing ppt then transfers to soil and reckons this has
advantages of no infection, faster growth, better recovery of
transformants)

Thanks for all the suggestions

Justin


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