I missed the time frame to spray my cherries for leaf spot, is there a fungicide that stops an already occurring infection?
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I hope so or my Montmorency cherry is a goner
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Do you apply anything as of now or are you thinking of a specific one
@Palmy_Oceans @poncirusguy
Bacterial leaf spot on all Genus Prunus & interspecifics is a gram-negative bacterial infection.
It is triggered by unchelated Ferric Oxide Iron.
Mixing 1 teaspoon Citric Acid per gallon of water & saturating all above ground surfaces can reduce the severity of the problem.
It doesn’t kill the bacteria, it simply causes it to transition from invasive pathogenic behaviors to benign dormant status.
You need to spray weekly to use Citric Acid as a control.
1 teaspoon per gallon as a foliar & bark spray.
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Immunox or captan works great. You will lose all leaves infected now so don’t wait to long.
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mine had it lightly last summer. only lost the lower 1/4 leaves. sprectracide immunox is a good preventative. it wont save infected leaves but will protect the uninfected from getting it.
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Ok is immunox systemic
Immunox organic?
Far from organic it’s a fungicide. The complete opposite of organic but it works.
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I meant like is it safe for use if I eat from the tree? Also is it a systemic?
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It doesn’t wash off so my opinion no its not safe during fruiting season. Never spray with fruit on my trees. Harvest my fruit then I spray
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Please google and Read the label of Immunox. It will tell you when to spray on what, how much and how long before you can pick fruit.
You need to read the label of materials you want to spray your trees with, no matter if it is organic spray or not. Organic does not mean totally safe.
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Alright, that’s my situation, by next year things on the branches clear up right?
This is the exact one we are talking about right?
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I prefer Liqui-Cop (or Kocide) and Abound, alternating through the seasons. For stubborn problems on some crops you can supplement the copper with Manzate Pro-Stick.
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While your suggestions is valid & vetted, it is a post problem treatment, not a prevention.
Usually when bacterial leaf spot happens it is because soil is not well enough aerated, plus gram-negative bacteria in the soil are too high in relationship to Mycorrhiza & wild soil yeasts.
In such cases (mycorrhizae & yeast) make primary Ethyl Alcohol from sugar from plant roots, not acetic acid & Glycerol gets created by anaerobic bacteria.
The gram-negative bacteria in the soil then use Glycerol as a metabolite to manufacture enzymes which allow them to produce Indol.
Because soil is not well aerated, the Indol gets absorbed by the plant rather than evaporating to the atmosphere.
Excess Indol entering the plant without Acetic acid, results in excess Indol in the leaves.
As the Indol evaporates from the leaves, it as well as unchelated Iron aka Ferric Oxide, trigger virulence of the aerobic gram-negative bacteria Xanthomonas which causes leaf spot.
While plants are often benefited by microbes making small amounts of (acetic acid & Indol) in the creation of Indol-3-Acetic root growth hormone, too much Indol or acetic acid can result in the death of plants.
Using an Iron product other than Iron-EDDHA, often results in too much Ferric Oxide in the soil, also facilitating the problem.
Canker is another disease that happens for the same reasons
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Simply adding aeration holes to soil & adjustment of pH with Citric Acid can dramatically reduce the chance of plants getting bacterial leaf spot!
Soil aeration helps soil mycorrhizae & yeast make acetic acid.
Citric acid chelates soil Iron.
Plus reduces the creation of Indol by soil bacteria,
greatly reducing invasive microbe virulence.
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