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<pre>Here is some information I gleaned from Dr. Steve Lindow, University of
California Plant Pathologist, Berkeley Calif. who has done considerable work
with frost protection materials over the years as they effect ice nucleating
bacteria. Of course, this information, by design, relates to California
crops but should have some utility (indeed a starting point) for
understanding the potential for olives. Here are his comments:

"The most effective frost control material for most crops is simply copper
compounds - they are registered on most crops and, if applied as a
preventative as far in advance of the frost as possible will generally
provide significant frost control. This is what we recommend for use of
citrus for example, where the coppers are generally applied about the end of
October to prevent the growth of ice nucleation active bacteria on citrus as
the weather turns cooler and wetter in the fall. Coppers also work on
spring frost such as on tomato etc. but generally must be applied shortly
after emergence and periodically to maintain a protective covering on the
plant (much like any other protective fungicide). The antagonist bacterium
Pseudomonas fluorescens A506 (BlightBan A506 also works well on certain
crops such as pear and apple, and is also applied to plant before a
population of ice nucleation active bacteria have built up - it acts by
competing with ice nucleators as they try to grow on plants.
Frostgaurd has little effect on frost as far as I have ever seen. We did
some tests on citrus a few years ago and saw no effect. It is based on some
of my earlier work in which I showed that protein denaturants could be used
as a "day-before" treatment to inactivate bacteria ice nuclei. This is
still an effective strategy, but none of these agents is registered, and
although some such as urea will not need registration, I have not pursued
this for a while. As I understand Frostgaurd contains sugar water, and some
copper salts, but at the concentrations that it is used probably could not
act as a nucleation inhibitor."

Hope this helps.

Steve Sibbett
U.C. Farm Advisor
Phone - office 559.733.6486
Mobil 559.280.0666
FAX 559.734.2708

-----Original Message-----
From: Margaret Chidgey [mailto:chidgey@mpx.com.au]
Sent: Friday, November 17, 2000 6:48 PM
To: OliveOil@egroups.com
Subject: [OliveOil] Frost protection methods


I'm usually a very quiet observer on this list, but I am interested to know
about olive trees and frost. In particular, is anybody using a product on
their trees that is designed to minimise frost damage? I would like to
write an article for the Autumn 2001 issue of The Olive Press on this
subject, but don't want it to be one-sided. Any information that anyone on
this list could provide will be gratefully received.
Thank you in advance,



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</pre>
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