Hi Tim! nice to read you!
I think there are more sources of fire blight bacteria in the general
environment in the northeastern USA due to your woodlots and forests (with
feral apples and native hosts such as Hawthorne) as contrasted with the
treeless conditions around many eastern Washington orchards.
I agree! But still is fascinating to see whole areas without FB and others with
FB, despite similar weather.
We often make “false positive” predictions because of this = conditions are
great for FB, but not FB develops because bacteria are simply not there. We
have nice qPCR data throughout bloom to prove it.
The bacteria (in the hypanthium) need to thrive in the nectary in order to
reach numbers sufficient to switch on their virulence. Once this is
accomplished you have an infection.
Do you have a good reference for me on this specific topic? When I reviewed the
literature, I only found a few things from Pusey. This might explain some cases.
We can learn a great deal about interpreting models by looking at the weather
data around the time that we are fairly certain that isolated infection events
occurred. We can also look at when expected infections did not occur. It
would be very helpful to me if any of you would share weather data including
rainfall, hourly temperature (or daily temps) and especially leaf wetness
readings. Please send data that covers days from first bloom to about 3 to 4
weeks after petal fall. Excel files are a real time saver.
We’re Also looking for the same type of data…!
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