The dreaded F word (Fireblight) is showing up in our orchards


#61

Thats good advice, you get the urge to remove it all immediately but that might not be the best path. Its also important to be vigilant for any ooze as those strikes are the only ones benefitting from removal. The ooze starts milky white and quickly turns orange. I find that if blight is not all that rampant I have few oozing strikes, maybe one in 30.


#62

It’s the least affected. I cut out a big canker on its trunk last year. No sign of fb in that area this year. I actually cut the top off of it and grafted on two sticks of hooples antique gold. The grafts grew to about 8 inches then got fb so I had to cut then off. Major bummer. But the rest of the tree has only had a few minor strikes.


#63

Yea, I really had the urge to cut it all out! I was in a panic about all the new shoot blight and I followed what I thought was “best practice” to cut the infected shoots ASAP. Fortunately, I eventually got the right advice from someone with major experience managing FB in multiple research orchards in my state. He really saved my bacon.

I thought I had avoided the “dreaded F word” this year. I’m way past bloom with only a few strikes, but last evening I had a major storm with high winds and about 15 minutes of dime sized hail. Looks like I get to learn about FB caused by weather trauma this year! The Apogee on the older trees helped limit the tender new shoot growth so I hope they will be OK. The new Geneva trees that did not get the Apogee may be another story.

The standard recommendation for trauma blight is strep withing 24 hours. Fortunately I had a one bag of strep left and I sprayed it this morning. Otherwise the FB infection could have been out of control before the store opened and I could get the Strep on Monday…

Growing apples is hard.


#64

Live and learn/read. In my haste to taste fruit from some grafted in scions from 2016 I went around hand pollinating some late blooms. Coincidence or not but this is when I started noticing a few FB strikes.


#65

Fireblight has devastated my goldrush apple this spring, after bypassing it completely the past two years. Its mostly shoot blight, which I keep pruning out because the infected shoots are oozing. Meanwhile, two nearby unknown heirlooms which were hit hard last year are almost untouched.


#66

A small Maxine pear got 18 inches of the 24 inch tree removed yesterday.


#67

Seems a shame to hit a like button on these posts…:frowning:


#68

@scottfsmith So do you leave the benign strikes until dormant season?


#69

I leave many of them. Blossoms I find pretty easy to pull off so if I’m looking at one I often pull it off. they usually don’t get re-infected.


#70

I don’t think I would have noticed the blossoms if I hadn’t been bagging the pears


#71

So if I discover my FB strikes oozing white or orange, I should prune out the branch to below the strike or ooze.

My question is about sterilizing my pruners between cuts. How often should it be done? Every single time you make a cut or just when moving to another tree?


#72

I immediately cut these out. I sterilize before and after I cut. I also put a little alcohol on my finger and rub it on the fresh cut. If it is oozing I also rub the alcohol on my hands. This is my method but it would be interesting to see how others proceed.


#73

In the latest and wettest spring recorded in this area (the next worst was in the 1890s) I found one blossom batch of Médalle d’Or/Gen11 wilted and discolored. Cut, and disinfected pruners. No strikes on Hunt Russet/M26.
Hunt and Md’O are the only cvs I have that are susceptible.

Bardsey/EMLA26 bloomed until yesterday - has an amazing extended bloom after the initial rush. No strikes despite conditions. I’ve never heard of FB on Bardsey, but since it is so little known kept an eye on it. BTW, this had a few sample blooms the past two years, but this year pushed about 100 spurs and tips.

Contradicting notes regarding Rambour Franc/Gen30 and FB left me jittery. First bloom (300 spurs and tips) this season and no sign of FB! Looks like a lot of thinning to do in a few weeks, as it got pollen from Wynoochee and Bardsey.


#74

For pruning off fb infected branches, I’d disinfect the pruner for each cut, not each tree.

For regular pruning, I do disinfect my pruner after finishing pruning each tree. Some trees are more susceptible than the others. I’d rather be more careful than not. I just use Clorox wipes, easy, not very economical.


#75

If one wanted to be really super careful when pruning out strikes, you could go out and paint Kocide on the spot you want to make the cut the night before then come in the next day and make the cut. Or spray bleach on the cut site right before making the cut.

That should whack back the FB bacteria and hypothetically help to minimize infection at the cut site.

I wonder if there is a correlation between the apple/pear microbiome and incidence of FB outbreaks?.. Lots of research coming out now indicates that too much cleanliness and washing in humans (and other mammals) can actually have a negative effect on health and the human skin, and internal gut microbiome. The natural inhibition/outcompetition of FB is probably part of the way that the Bacillus subtilis (Serenade) sprays work.

Makes me wonder if nuking the natural microbiome on apples/pears with copper/streptomycin might set you up for a cycle of needing to spray and increased number of hits from FB. All speculation, of course, but something to think about.


#76

Have a confession about cutting out FB which is I never really cut out fireblight. I break the branch off typically and then cut off a little more so my pruners never touch the fireblight. It’s just something I do and never saw anyone else do it then I disinfect the pruners. When I see people wipe the pruners with alcohol that just touched the fireblight I always think it’s not enough.


#77

I often do the same thing, but I break off most of branch, so there’s
no need to prune at all. It’s the lazy man’s way of pruning off strikes,
when I don’t have pruners with me.


#78

I’ve seen university recommendations that said ripping out the smaller strikes is a preferred method because it’s less likely to spread the bacteria. Many people probably don’t cut back far enough and don’t sterilize well enough between cuts. So they are just spreading it around.


#79

What’s the latest on Geneva breeding work to bring Kazakstan blight resistance/immunity into our domestic U.S. apple varieties? Is this a 20 or 30 year project?


#80

I think there was an article about along these lines in Good Fruit Grower recently, but they were trying to breed in resistance to post-harvest disorders. http://www.goodfruit.com/taming-traits-from-the-wild-genome/ They were using genetic markers to speed up their breeding efforts.

I would suspect it would be faster with CRISPR/Cas9, but some folks would probably get their panties all in a bunch because it is genetic modification (even though the genes would be going from apple to apple). So for now, everything has to advance at the pace of conventional breeding.