North American Fruit Explorers mailing list at ibiblio

[Alan Haigh <alandhaigh@gmail.com>]

If you have 10,000 trees or a million all on one orchard you can only hope to become expert of what fireblight is likely to do where those trees are.  Like all pest issues how FB is likely to behave is regional (mostly weather) and probably sometimes local.  The other factors are varieties and root stocks.

 

I have heard of commercial growers upstate a bit from me loosing hundreds of trees on dwarfing root socks to infection, wiping out their whole stand of Honeycrisp for instance.

 

I don't grow much on dwarfing rootstock and on scores of sites only 2 pear trees, both Boscs, have ever been hit hard enough to even be disfigured.  Fireblight has only been damaging at 3 of the sites I manage, and I have no idea why there and not at the many other sites with the same varieties growing.  That's not to say that I couldn't come up with an educated sounding theory.

 

On one of those sites one year FB did a lot of damage to the apples, especially a Honeycrisp and for the last 2 years there's only been a little damage on the pears and none on the apples.  The Bosc pear on this site, which is one that has been disfigured had no FB damage this year while the Seckel and the Red Bartlett did (I know, I know, different flowering period, but it is shoot blight I'm talking about).

 

I am speaking from about 2 decades of protecting fruit trees at many sites in the southeastern NY area, and I can say that FB has me pretty much bewildered, even with the benefit of Dennis's sage advice.