North American Fruit Explorers mailing list at ibiblio

["Moyer, Richard" <ramoyer@king.edu>]

Both TFB and Joe Hecksel wrote about pear traits.  We had two bad fireblight
years in a row which is very unusual, but it appears that the first was due
to infection at bloom and the second to two severe hailstorms well after
bloom.  Different sets of pears and apples were infected each year,
including fireblight after hail on apples and pears noted for blight
resistance.  Happy to report that Korean Giant, Shinko and Wm. Pride
unphased both years, but I did lose a Seckel tree this year, and it had not
blighted before through bloom or tender growth.
Asked Dick Bell about this, and he noted that both Seckel and Magness are
quite susceptible to fireblight following hail damage.

Hence, it appears that Magness and/or Seckel are primarily resistant through
blooms and tender new growth. June drop, hail and Cicada damage are each
additional routes for fireblight infection.  TFB, could these latter two
have opened your Magness to infection? 

Hence my suggestion that PART of the reason for divergent observations in
blight resistance may be due to different routes of blight entry, which vary
year to year, along with spells of warm, humid weather.

I also am limited to single trees for most of my observations, a very
valuable point.

Yet, within NAFEX are folks who have been trialing many pears for many
years, and can give info on which pears are survivors under their
conditions.  For more info, go to NAFEX Pear interest group @
http://www.nafex.org/soupear.html.
I have a 2000 article on pears for my region @
http://www.king.edu/faculty/moyer/; fireblight links therein.
Richard Moyer
East Tenn, Zone 6, 1800'


TFB wrote, in part:
>Just one caution, and this may "excite" a few people.  Before I planted a
whole lot of blight resistant pears I would trial them in my area.  I am
convinced that there are localized strains of fireblight.....  In fact since
1995 I have lost 4 different Magness fruit trees on various OHxF stocks to
fireblight.  And the wood was from different sources, one source was
Corvallis.   

On the other hand Harrow Sweet and Harrow Delight show a bit on some leaves
and branches now and then but it stays isolated.   Harvest Queen has yet to
get it, and nor has Potomac.   For that matter neither has my Barltlett, or
Bosc, supposedly sensitive trees.

I am just relating my experience, with limited numbers of test subjects
(singulars for all but Magness).   But it is something to ponder.