Subject: Frost and pear damage?

From: michael@helium (Michael Courtney)
Date: 13 May 1996 11:23:26 GMT

It got down to 27 deg F last night and my pear orchard (mostly
dwarf Seckels and Bartletts) was in full blossom.  The orchard 
was well-pruned and in good shape before the frost.  

What kind of damage can I expect?  Is all this year's fruit lost?  
Is there anything which I can do to help?

Does the late frost leave the pear trees more susceptible to disease
or  insect damage?  What preventive steps can be taken?

Thank you for your help.

--
Michael Courtney, Ph. D. 
[email-masked]

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From: [email-masked] (Scott Arighi)
Date: Mon, 13 May 1996 23:56:50 GMT

>Is there anything which I can do to help?
At 27 deg. it will be touch and go frome my experience.  At the least,
you'll likely get some fruit loss.  To help -- *pray* -- fervently.
>or  insect damage?  What preventive steps can be taken?

Frost during bloom seems to make pears, particularly D'Anjou but also
some of the others as well, more susceptible to  pseudomonas blight,
which is sometimes confused in appearance with fireblight.  A copper
spray *before* bloom sometimes helps prevent this problem.  Probably
copper won't help at this point.  Hope for the best.

--
Scott Arighi

Those who ignore history are doomed to repeat it.

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From: [email-masked] (Pollinator)
Date: 13 May 1996 20:47:03 -0400

In article <[email-masked]>, michael@helium (Michael

>or  insect damage?  What preventive steps can be taken?

   Look at the pistil.  If it turns black, it is ruined.

   A factor that gives a slight edge in situations like this is
pollination.  Did you get in plenty of bees, early enough to get quick
pollination?  Once this is done, the outer parts of the flower are not
needed.  This may be only a couple degrees' worth of protection, but often
that is enough.

[email-masked]    Dave and Janice Green,  PO Box 1200,  Hemingway,  SC
29554

Practical Pollination Home Page
http://users.aol.com/pollinator/polpage1.html

[email-masked]                                   Dave Green
Practical Pollination Home Page    
http://users.aol.com/pollinator/polpage1.html  
PO Box 1200, Hemingway, SC    29554

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From: [email-masked] (Jonathan Bishop)
Date: Tue, 14 May 1996 01:28:07 GMT

>or  insect damage?  What preventive steps can be taken?

Michael, according to a chart in the Cornell Tree Fruit
Recommendations, 27 degrees can be expected to kill about 10 percent
of the flowers. As the temperature goes down, higher percentages will
be killed with 90 percent kill at about 24-25 degrees. keep in mind
that most fruit crops need thinning anyway so as long as pollenation
and everything else goes well, 10 percent damage is tolerable.

The main worry on Pear trees in spring, frost or no, is Fire Blight.
Infections occur under warm moist conditions. A lot depends on how
much inocculum is around. If you are fairly isolated from other
susceptible species, and you haven't ever had it, it probably isn't
likely to be a problem .

Pear Scab can be a problem in some areas of the country. Fabria is
another potential disease problem.(neither is affected either way by
frost) Both can be easily controlled by using one of the mancozeb
fungicides with Benlate beginning at White Bud. Be sure to consult the
label for rates and pre-harvest cut off dates. (Mancozeb can't be used
later than 77 days pre-harvest).

Frost won't have any affect on susceptibility to insects, although
severe winter conditions with little snow cover can sometimes affect
survival of the overwintering stages.

Good Luck,
Jonathan

¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿

Jonathan Bishop                       Bishop's Orchards
B.W. Bishop & Sons, Inc.              Growers of Fine Fruit
Guilford, Connecticut                 since 1871
E-Mail:[email-masked]

??????????????????????????????????????????????????????????????

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From: michael@helium (Michael Courtney)
Date: 14 May 1996 11:22:34 GMT

Jonathan Bishop ([email-masked]) wrote:
: michael@helium (Michael Courtney) wrote:

: >It got down to 27 deg F last night and my pear orchard (mostly
: >dwarf Seckels and Bartletts) was in full blossom.  The orchard 
: >was well-pruned and in good shape before the frost.  

: >What kind of damage can I expect?  Is all this year's fruit lost?  
: >Is there anything which I can do to help?

: >Does the late frost leave the pear trees more susceptible to disease
: >or  insect damage?  What preventive steps can be taken?

: Michael, according to a chart in the Cornell Tree Fruit
: Recommendations, 27 degrees can be expected to kill about 10 percent
: of the flowers. As the temperature goes down, higher percentages will
: be killed with 90 percent kill at about 24-25 degrees. keep in mind
: that most fruit crops need thinning anyway so as long as pollenation
: and everything else goes well, 10 percent damage is tolerable.

Thanks for the helpful info. Pollinator wrote and said to look for black
pistils as a sign of damage.  In one part of the pear orchard there was
90-100% loss.  In another part there was 20-50% loss, so I guess there
was some temperature variation with location.  In any case, what the
first frost didn't get, probably did get destroyed last night:
25 deg F.  A few buds were still closed on some trees, so maybe it's
not a total loss.  I've only got about 50 pear trees and 50 apples
and my livelihood does not depend on it, so I suppose things could
be worse.  The apples haven't come into blossom yet, so I am hopeful.
But I like pears a lot more than apples, and the apples are much more
prone to disease.

--
Michael Courtney, Ph. D. 
[email-masked]

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From: [email-masked]
Date: Tue, 14 May 1996 14:55:04 GMT

Fortunatley, cold air pools at the lowest spot. If you didnt immediately
see darkened blossoms the next morning, the blooms are probably OK. We had
a foot of snow on our apples a few years ago and they did fine (the
branches which didnt break). I dont think it will affect the trees at all.
I have been trying deep mulches on my dwarfs to keep them cool so they dont
bloom too early (not really a problem this year!). Ingrid

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From: michael@helium (Michael Courtney)
Date: 16 May 1996 11:14:42 GMT

Welland High School Stn 20 ([email-masked]) wrote:

: Living in Southern Ontario, when is the best time to pick the bartletts?

Probably late September, but someone closer to you could offer a better
estimate.

--
Michael Courtney, Ph. D. 
[email-masked]