Black rot and other fungal diseases

sunkirstAugust 24, 2014

It's been a really cool, wet summer here, and I feel like I'm being overrun with different fungal diseases. It started with black rot in my kale, which has spread, despite tearing out the initial planting and spraying all my other brassicas with copper soap.
Of course my tomatoes are affected. I mowed down all my parsley because of a leaf spot, my melons just bit the dust, and walking thru this morning, I noticed rectangular lesions on the leaves of my sweet corn (which is almost ready).

I'm a little freaked out, especially about the black rot. I've read all about it, and I'm hoping that crop rotation, and keeping culls out of the compost will prevent a re-occurrence next year. I'm spraying copper weekly on my broccoli, cabbages and cauliflower, and I'm still seeing evidence of the disease, although it's slowed down.

Questions: Has anyone used Actinovate for preventing fungus? I know it's not supposed to prevent black rot, but I'm seeing sooo many different diseases.
Any other recommendations for helping with disease (I already use lots of compost, follow the organic amendment recommendations from Logan labs and rotate crops - in blocks - I'm thinking of separating my beds of brassicas and tomatoes next year so that disease can't go thru the entire block so quickly)
Also, would you just pull all the brassicas and take the loss, or can I allow stuff to mature? From what I read, the disease is systemic, and if it's on the leaves, it's infected the entire plant(!) but my cabbages are heading nicely, despite it all.


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try oxidate, a hydrogen peroxide based fungicide. It should be ok if you are certified Organic

    Bookmark   August 25, 2014 at 9:02AM
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Thanks, I'll give it a try.

    Bookmark   August 25, 2014 at 10:59AM
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Mark(Oregon, Zone 8)

I've had fungal issues mostly with grey mold, white mold, powdery mildew and downy mildew. Black rot only on celery but it may be a different type than you describe.

I've tried both oxidate and actinovate and they both work, but very differently. Oxidate kills on contact, like a cleanser. I use oxidate when i've seen an outbreak and feel like it could get out of control. Once sprayed, the leafs are clean of all fungal/bacterial parasites and as I understand it, also all it's beneficials, so now it's susceptible to further attack as soon as more spores land.
Acitinovate is different, it's a preventative. It's used before the outbreak happens but when conditions are present for it to occur. Actinovate is a bacteria that occupies space on the leaf surface competing with and hopefully limiting potential threats from taking over and multiplying.

Using both types of spray is probably the best chance you have. Actinovate first to help deter, then oxidate if needed, followed again by actinovate to re-occupy the now susceptible leaf surface.

Hope this helps, and FYI this is just my understanding of this fairly complex process. I'm sure someone with more scientific background could add much more.


    Bookmark   August 27, 2014 at 12:21AM
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Thanks, Mark! I appreciate your clarification. Looks like I should have Oxidate, Actinovate and my old standby copper spray on hand for next year.


    Bookmark   August 30, 2014 at 9:13PM
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