bacterial canker Archives

Field results of nutrition management on freeze resistance, bacterial canker and powdery mildew in cherries

From the podcast interview with Mike Omeg:

John: Mike, you’ve been talking about the returns in very abstract terminology of return on investment, etc. Tell us about results. What has changed with your trees? We started this conversation by mentioning a desire to develop the root systems. What has changed with your root systems? What has changed with tree health? What have you actually observed in the field?

Mike: I have some anecdotes and then I have some actual data to share. Let’s start with the anecdotes.

In November of 2014, we had one of those once-in-a-lifetime historic freezes. The lowest the temperature had been was 43 degrees. Our trees generally go into dormancy in November, but it had been a very warm fall and the trees were still actively growing. We hadn’t had any acclimation to the cold. Then we had an arctic front come down, and we went from lows in the 40s to below zero in one day, and it stayed below zero. Here at my house, we had -4 degrees Fahrenheit.

The leaves on the trees just turned black. Just like a dahlia plant looks after the first frost, the leaves turned black, and they just hung on the trees. Several hundred acres of trees in our area just died. We had blocks where all the buds were frozen on the trees.

At that time, I was doing some comparison and analysis between mulch and intensive bionutrient applications and conventional applications for management of the orchard. I had two orchards that were sitting within a quarter-mile of each other at the same elevation. One was on one side of a small canyon and one was on the other. They were the same age and variety of trees and had the same irrigation. The only difference between them was the nutrition management. One had received compost mulch and bio-intensive nutrition, and the other orchard was just a standard conventional orchard.

After that freeze, all the trees in the conventional orchard were dead. They froze and the entire canopy was killed. We could have regrown them from the roots, but the trees were dead down to the soil. The entire orchard was smoked. There wasn’t one tree left. When you went and cut bark, it was black underneath instead of bright green. I had to remove that orchard the following spring

The orchard where we’d been following these bio-intensive practices, believe it or not, had 110 percent of a normal crop that year. We actually picked 10 percent more fruit out of that orchard than we did the previous year. That truly amazed me. That difference was only due to the nutrition management and these other activities that we were doing. There was no other difference.

The other thing that we’ve observed over time is a marked reduction in two pathogens that are problems for us with cherries. One of them is bacterial canker. Bacterial canker causes cherry trees to eventually die. They create a lot of gum. The trees get a canker that has a swelling of sap under the bark, and then these cankers burst, almost like a blister, and sap oozes out of them. That disease is a particular challenge with certain varieties and certain rootstocks of trees. If it doesn’t wipe the orchard out, it takes enough trees out that you lose the value of that block as an economic unit.

The consultants at Advancing Eco Agriculture I work with started to tell me that we should try to take on bacterial canker by focusing on nutrition. Over time we had an amazing transformation in a block that had significant amounts of bacterial canker—enough that I was going to take the block out. But I left it there because I didn’t have anything to lose.

Bacterial canker was actually eliminated from that block. It wasn’t just reduced—it was actually eliminated. Virtually all of the trees in that block had one or more canker sites on them. Some were far worse than others, but almost every tree had at least one canker on it. By the third or fourth year, we could not find bacterial canker in that block. I had neighbors coming to the block. I had extension staff and research pathologists from Oregon State coming to that block, and they could not believe the change.

The second disease that is more problematic in cherries is powdery mildew. That disease affects the foliage and fruit. It’s a real challenge. Powdery mildew is the disease that is targeted by almost all the fungicide applications that are applied in conventional and organic production of cherries. What we’ve seen is that highly susceptible varieties normally would require extra powdery mildew applications. But we’ve been able to reduce our applications by half, and maybe I could reduce them by more—I’m just a bit nervous about reducing them by more. But we have been able to apply half the number of fungicides to those trees, and we have no mildew there.

This is another thing that neighbors couldn’t believe, so we actually had a walking tour through that block. One of them was hosted by extension. I made a bet with the neighbors—I said, “Find any mildew in this block and I’ll buy you a steak dinner.” I’ve never had to buy a steak dinner because folks can’t find mildew in that orchard. A typical orchard with that variety in it would have lots of mildew because even with fungicide applications we are not able to control it.

Those are two things that that we’ve observed that I honestly thought would never happen. Through nutrition, we’re able to manage our diseases—in this case, with bacterial canker, and with powdery mildew. It speaks to the long-term value to the orchard of providing the nutrition that the tree needs. Do that and the tree will take care of itself.

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P.S. I am hosting a Zoom video AskMeAnything discussion on Friday at 1 PM EDT. You don’t need to register in advance, just connect here at 1 PM. See you there!

Reversing bacterial canker on cherries

Bacterial canker is considered an untreatable infection in stone fruit and cherries. When the infections become severe enough, the block of trees may be pushed out and replanted for a fresh start.

Our experience indicates it is possible to reverse bacterial canker infections. We can’t point to a specific nutritional profile or disease suppressive soil microbial populations as having produced the resistance. We used soil mineral analysis and plant sap analysis and fine-tuned soil amendments, fertilizers, and foliar applications based on the results. Bacterial canker disappeared from trees that had previously been infected to the point of being destined to be pushed out the following year. Today, these trees are a productive block five years after the initial applications were made.

Lynn Long and I discussed this specific cherry block in our conversation on the podcast here.

John: We’ve worked together on some orchards where we’ve seen some interesting things concerning bacterial canker. At one farm that we at Advancing Eco Agriculture have worked on, the incidence of bacterial canker has been greatly reduced―I think to the point where now, after several years, we can say that it seems to have been eliminated on a couple of blocks. Many growers have asked what we did and what products we used.

And the answer, as Lynn has pointed out so well, is that we don’t know. We worked with nutrition products, we worked with biological products, and we tried to manage that ecosystem. As the ecosystem changed, bacterial canker pressure changed. We can’t point to one thing and say that we did one thing that made a difference. I agree with you that there seems to be the potential to shift that disease in particular, and perhaps others as well. This would be really exceptional.

Lynn: Bacterial canker is a disease that is pretty relentless once it gets into the tree. Occasionally, you’ll find that the canker will dry up and will not progress any further, but much more typically, once it’s established, it will continue to grow and expand and will eventually kill part of the tree, or all of it.

When this grower approached me, he mentioned that he was having some severe infection with bacterial canker. There’s really no effective chemical that you can apply on that tree that is going to stop an infection once it’s started. You can help prevent infections by using some products. One particular product would be copper, but even that’s not all that effective.

When I saw this orchard, there were infection strikes all over the trees. It really did not bode well for the future of that block. But then the grower started to do some of the things we’ve been talking about―using compost and mulching and using some of the AEA products. As I’ve mentioned before, we can’t point a finger to any scientific data that says this turned it around. All we have are observations.

After the first year, the grower came back to me and said that those cankers had dried up. This was in the summertime, and these cankers do go dormant in the summertime. I thought, “Let’s see what they look like in the fall and then in the spring, and we’ll make a better assessment then.” The next spring came around, and the next summer, and the cankers had stopped. For two or three years I went back to that block and continued to look at it, and I saw no more advance of that disease. The oozing that comes about as a result of that disease―from the sap coming out of the tree―had totally stopped. The infections had dried up. It was pretty remarkable. It was quite atypical of what we would have expected for a commercial cherry orchard that was so badly infected.

P.S. Several weeks ago I wrote about our observations preventing and managing spider mites predations with nutrition, which we have been quite successful with. Today at 4 PM EDT AEA is hosting a webinar where we will describe the plant nutritional profile that allows spider mites to be present, and how you can shift away from this profile. If spider mites are a challenge for your crops, you won’t want to miss it. You can sign up here.