"David Hare-Scott" wrote in message

"My zuccs have BER!"

"As I understand it the problem is due to deficiency of
calcium in the plant which can be brought about by uneven water availability
or lack of calcium in the soil.".

Absent more specifics, I believe that is more SWAG than fact.

Consider the chemical distribution of Ca w/in the plant.
Most likely your plant's available calcium is being diverted from the fruit
& going to the leaves where it is needed more at that particular time, say
for transpiration.

Ca is not a mobile nutrient, i.e. going where it is best needed. If BER
occurs when temps are high, try slowing the plant's transpiration rate to
get a better Ca distribution. Note, even if you have adequate soil Ca, its
uptake can be limited by other factors such as listed in the Spectrum
Analytic article* below . If BER is a constant problem, try the
preventive measure outlined in the ISHS abstract ** below.

The soil has been amended with lime and gypsum.
They are growing strongly with a multitude of flowers and fruit setting.
One odd thing is that normally this strikes on the fruit when they are
quite small but this time they are getting nearly to cutting size before
it starts.

I'm curious; did a soil analysis/test indicate you needed the lime and
gypsum or is this just a gardening "best practice" method?

If you care to share; what type is your soil, pH, amendment regime,
fert/schedule, etc.?

"Any ideas from experience?"

"Any references to a detailed explanation of how BER happens..."

Try these:

* http://www.spectrumanalytic.com/supp.../Ca_Basics.htm

** http://www.actahort.org/members/show...knrarnr=145_23

http://www.springerlink.com/content/ww87lw2086rj3v71/

http://jxb.oxfordjournals.org/cgi/co...tract/44/2/509

General reads on BER:
http://pubs.caes.uga.edu/caespubs/ho...ossom-rot.html

http://wihort.uwex.edu/fruitveggies/TomatoDisorders.htm