[nafex] fireblight, etc.
Ed & Pat Fackler
rocmdw at aye.net
Fri Jun 22 05:10:34 EDT 2001
I've been reading a bit of what's going on regarding fire blight with
great interest. For the nine years that I have been
growing fruit trees I have had very little incidence of fire blight.
The little fire blight that I had was in a few of my quince
trees. I haven't been very diligent about spraying my trees either, I
might add. As a matter of fact, one of my resolutions
this year was to be more proactive/intelligent with my spraying. I did
my dormant oil and ferbam and continued with
imidan (thank you Harvey Lisle) and manzate. I, for the first time,
also applied streptomycin with my imidan/manzate
spray. Perhaps I applied the streptomycin too late, perhaps this year
was perfect for the growth of the fire blight
bacteria or perhaps I was too lazy regarding orchard sanitation. Either
way, I have been walloped with a bad dose of
fire blight on my seckel pears and a few apple trees. I have cut out as
much dead/diseased wood as possible and have
sanitized both the wound/blade with rubbing alcohol. The bacterium
progresses. At this point what should I do? A local
professional orchardist said to not spray anymore streptomycin as I
would be wasting money. He said to let the fire
blight take it's course and prune it out this winter. What is the
recommended course of action? Is it too late to apply
streptomycin? I appreciate any and all advice. Regards, ken
Well firstly it is good to hear that Harvey Lisle is well and still
Secondly, go with the advice of your local grower. The reason why
he advised against applying more strep now is that strep is systemic
only to localized areas, primarily to fruit spurs and related tissue
(leaves). Also, after symptoms are visable, the infection is at least
10 days, perhaps 15 days old and well within older wood. Or, strep
simply can't influence the bacteria after 24-36 hrs. of infection.
Also throughout the eastern US this year, infection conditions were
many (rain, bloom and high temps). Also, there were many post bloom
infection conditions (thunderstorms with hail and high winds--which
equals trama blight).
On older, less vigorous trees, fireblight bacteria doesn't
translocate as well and trees will wall it off, generally at a point
where two to three-year old wood exists. I think this process is called
This winter, prune out all damaged wood and next year do a decent
job in early season spraying (bud bread through post bloom).
In my view, the above is about it.
Hope this helps.
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