California Frost Prevention 
Steve Sibbett
U.C. Farm Advisor

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."

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

Frost Prevention notes from New Zealand
Neville Burt

1. Plant the most suitable varieties for your conditions. (in my case Leccino, Frantoio, Pendolino and Maurino).

2. Plant new trees after the last expected frost date to give maximum period of acclimatisation, before winter frosts.

3. Maintain area around tree free of weeds

4. Maintain moisture levels in soil especially over winter.

5. Avoid use of high nitrogenous fertilisers as these can cause soft growth easily damaged by cold.

6. Spray trees 10-14 daily with a product with frost reducing activity (I use kelp and EM-Effective Micro-organism)

7. Maintain organic matter around the tree to assist nutrient recycling and moisture retention.