The situation:
In my orchard there is 1 five year old cherry tree, 2 2yr old cherries, and 2 seedling asian pears. The orchard is located in wonderful sandy loamy soil that is near a creek, and fairly low on my land. However, I've never found it to be overly damp and placed the orchard there because temp/moisture levels seem to be more regulated there than anywhere else.
Im looking forward to planting a large number of fruit trees this next spring, but am wary because many of the trees Ive planted over the last couple of years have died, and the ones that survived are now suffering from what appears to be a similar disease.
The largest cherry has bad bacterial canker covering all of it's smaller branches and new growth, thankfully it doesn't seem to have gotten on the trunk or any main scaffold branches. The younger cherries have 6inches of die-back this year and each have 1 small canker on them. Last year I planted 3 asian pears that all died, and this year, within a month of planting asian pears I now have one with a branch turning black.
My hypothesis:
1) The soil's not great, these trees hadn't really been mulched properly, or ever fertilized in any way. They are surrounded by grass. Really they've been neglected up until now. Damage from frost, borer moths, lack of nutrition, and competition from sod all create stresses which can lead to disease.
2) It seems like the disease has spread REALLY quickly, and effected many of the trees I have planted. This could be because the oldest cherry tree is badly infected and spreading innoculum. I've also read that pathogenic nematodes, such as the ring nematode, can be a vector for these types of fungal diseases in stone fruit, and that they like rougher soils. It could be that there is a high population of these critters in my sandy orchard and that is helping spread disease.
Solution:
1) Take care of the trees. I've mulched large rings around all of the trees, fertilized with compost, and am beginning to plant benificials and dynamic accumulators/nitrogen fixers in the tree understory (even for the young trees that dont really have an understory yet). Also I'm trying to create good wildflower habitat to draw beneficial insects to reduce pest pressure, this will help reduce stress on the trees and prevent damage that can lead to infection. I think transitioning the area surrounding the tree to different bulbs, flowers, and perennials MAY have some effect on pathogenic nematode populations if they exist. They seem to have relationships with certain plant root systems (such as grass).
2) Prune out infected growth during dry summer months. This is difficult on the large tree as SO much of it is infected. Thankfully no real trunk or scaffold branch infection but I'm leery of cutting off so much growth. I'll be applying a tree paste to the cuts that is made of clay, effective microbes, neem oil, calendula, and garlic. This will hopefully allow the cuts to breath&heal while still protecting points of possible infection.
3) Biodynamic sprays w/ the following ingredients..... For nutrition: Seaweed, comfrey, nettles, molasses. For competitive colonization of trunk and canopy: effective microbes. For canker supression: Garlic, nasturtiums, broad leaf dock, calendula. Also all of these sprays will contain neem oil, to help deter pests &disease and feed the effective microbes.
I'll also be spraying with copper this fall and next spring when the canker is active and spreading. I don't really want to, as this isn't really a holistic option, but I think it will help me gain an edge on the disease.
4) Paint trunks white to help prevent any winter frost damage. Also, rub a paste of Garlic, calendula, nasturtium, & Burdock directly on any canker spots that don't get pruned. I've read that these herbs are generally anti-microbial/fungicidal and can be specifically used to treat canker.
In The End...
As you can see I'm pulling out all the stops to help these trees and create a healthy orchard environment. Really though, I've read a lot of books and have no real-world experience or mentor to help me with this. I'd appreciate advice, or any experiences people could share about similar problems they've dealt with in orchard environments.
I just really don't want everything I plant to die and loose an enormous amount of time & money because I chose a poor location for an orchard, or because somehow my soil is secretly infested with pathogenic apocalyptic nematode critters.
