sterile thrips

Daniel E. Perazza daniel.perazza at
Wed Sep 23 10:53:14 EST 1998

Dear netters,

My original question was:
"I am currently having problems with some very important seeds stocks
contaminated by thrip eggs. These eggs appear to be resistant to common
sterilisation method (15min in 5% calcium hypochlorite), leading to
pest-contaminated-plants in "sterile" petri plates...
Any advice to get rid of these eggs without affecting seed viability"

Thank you to all who took the time to reply
For the people who (will) encounter the same problem, here are the most
relevant suggestions I obtained:

- UV irradiation (if they're on the outside) should work.  Toast the
under a germicidal lamp (like in a transfer hood) for hal an hour or so.

The seed coat's extremely UV-absorbent- this shouldn't affect
at all.  Shake the seeds around (or spin them in water) to make sure you

get the entire surface.

-we usually put seeds one night at -20 degree celsius,
making sure they cannnot get wet. This seems to be

-I've been told that a few days at -80oC will destroy the thrip eggs but
harm the Arabidopsis seeds.  You may want to explore this.

-try and induce secondary dormancy in your seeds. This
will prevent them from germinating without GA and cold treatment, and if
thrips eggs hatch before the seeds germinate it will be a lot easier to
them. Secondary dormancy can be induced with a 15 min far red light

-A colleague used Vapona 'No-pest' strips (I believe a Shell product) in
bags in a closet to get rid of viable insect eggs on seeds and/or bulbs.

-I used a tiny thrips-egg eating spider mite (ENTONEM from Koppert
Biological systems) succesfully last winter to control thrips
in my Arabidopsis in the greenhouse. Maybe they can 'clean'
your seeds, too (or snatch them up along with the eggs?).

Daniel Perazza
Department of Plant Sciences
University of Oxford
South Parks Road
Oxford   OX1 3RB

Tel       +44  (0) 1865 275027   (lab)
                        275139   (office)
Fax       +44  (0) 1865 275074
Email     daniel.perazza at

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