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Blackberry rust?

Posted by queenskitchen 7 nyc (My Page) on
Wed, Jul 9, 14 at 10:24

Is this blackberry rust? If so what is the appropriate treatment? I have neem oil on hand, that should work correct?


Follow-Up Postings:

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RE: Blackberry rust?

I forgot to mention that this is either ouachita or apache. Whichever has bigger berries (my kid pulled out the tags shortly after planting). I thought these were resistant to rust?

Here is another pic of the nice crop this year (on the plant without the "rust").


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RE: Blackberry rust?

  • Posted by Drew51 5b/6a SE MI (My Page) on
    Wed, Jul 9, 14 at 12:13

Neem oil will do nothing. It's pretty much useless. Strange to have it so late in the season. Most treatment is to remove infected plant and use lime-sulfur which is no longer made. No treatment known, only preventative fungicide sprays. Fungus is systemic and will remain with plant, year after year. You can harvest your crop, but best to destroy plant afterward. If this is truly rust? Looks like it I'm afraid.


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RE: Blackberry rust?

It's some sort of leaf spot fungus (rust, anthracnose, septoria, etc.). Lime Sulfur sprays before they plant leafs out helps slow the spread. Improved air circulation is probably the best solution because the leaves are staying damp too long. You can also remove the leaves that are infected to slow the spread too.

I'm pretty sure lime sulfur is being produced but it generally is only available through Ag extension offices or commercial farming supply stores. The big box stores don't carry it around where I live but the local Ag store does.


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RE: Blackberry rust?

Crap. I hate to toss this plant because it is the third year with it and biggest crop. Also concerned it may spread to my other Black. It is really thick where the rusty leaves show up and I have been watering daily. I will remove infected leaves and take care not to get the leaves wet when watering.


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RE: Blackberry rust?

  • Posted by Drew51 5b/6a SE MI (My Page) on
    Wed, Jul 9, 14 at 12:52

Best use some fungicide in the spring on other plants. Toss the whole thing, dirt too! It does suck as it's a nice looking plant. If you want to remain organic you can use just sulfur, or copper might work, also. I still have one bottle of Lime-Sulfur. 100 dollar offer I would refuse to sell. Best spray your other plants, like right now.
This is the worst rust I know of.
You can make a Bordeaux mix too, Google it, not easy, but an excellent organic product. Copper is considered organic, but you must be careful with all fungicides, it's terrible for the environment, but use on a small scale is very acceptable. A dropped old penny is worse for the soil.


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RE: Blackberry rust?

  • Posted by Drew51 5b/6a SE MI (My Page) on
    Wed, Jul 9, 14 at 12:57

OK reading more, looks like it is not that dangerous to most domesticated blackberries, so you probably do not have to spray your other plants. Here's an interesting read

Here is a link that might be useful: Blackberry Rust Fungus


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RE: Blackberry rust?

Had to take a call. I'm not a plant disease expert but orange rust is the only blackberry fungus, that I'm ware of, that requires you to remove the whole plant. Anthracnose and septoria leaf spot defoliate your plants but typically are not deadly to the plant. My plants have anthracnose and come back fine each year. All of the leaf spot fungus diseases will spread to nearby plants though.


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RE: Blackberry rust?

live and let live. I wouldn't spray unless it was affecting plant vigor or fruiting.


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RE: Blackberry rust?

  • Posted by Drew51 5b/6a SE MI (My Page) on
    Wed, Jul 9, 14 at 13:15

"live and let live. I wouldn't spray unless it was affecting plant vigor or fruiting. "

It will eventually.
Plus spraying will not kill it. i would not spray it either.

Good point JT, it does look like rust as he has had it 3 years, and the other plants are OK. I guess with that in mind, you might as well keep it as long as it produces and appears to be no danger to other plants. Once the rust starts killing the plant, then you can toss it.

This post was edited by Drew51 on Wed, Jul 9, 14 at 13:52


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RE: Blackberry rust?

Just look under the leaf at the other side and see if it has yellow or orange colored pustules (e.g. bumps). If it doesn't have pustules, then don't worry about it. If you hand water your plants, make sure that you are watering them at the base and not over top of the plant. Keeping the leaves dry will reduce / eliminate the fungus.

Here is a link that might be useful: Orange Rust Pustules


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RE: Blackberry rust?

I am pretty sure this is apache as Indiana berry confirmed that it would have bigger berries than ouachita. They suggested I take pictures of the underside and send them to to help ID. I am at an airport now but can check Friday when I am back. It definitely didn't look like your link jburton. It looked just like the spots on the top of the leaf if I recall correctly


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RE: Blackberry rust?

  • Posted by Drew51 5b/6a SE MI (My Page) on
    Wed, Jul 9, 14 at 14:33

It still could be rust, that was a serve case JT showed. Let us know what they say. In the article I linked they mention a thornless upright that is suseptable, looks like it is Apache! Keep us updated!


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RE: Blackberry rust?

No, Navaho is the thornless, erect variety that is highly susceptible to orange rust and black raspberries.


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RE: Blackberry rust?

Some new pics of top sides and undersides of leaves.
Topsides


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RE: Blackberry rust?

Undersides. .. What you think?


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RE: Blackberry rust?

From the pictures you posted, I don't think this is orange rust but it is some variety of fungal leaf spot. Looking through pictures online, it looks closest to cercospora leaf spot. You probably won't know for sure unless you get it tested.

Most of the fungal infections that cause leaf spotting are not immediately fatal to your plant, but will weaken it over time and make it more susceptible to other infections.

I posted a link for reference. Many of my blackberries get leaf spot fungus and they do fine the next year. Some varieties are more prone to fungal infections than others and where you plant them can influence how often it occurs. I have not yet found a 'cure' for this problem but lime sulfur treatment during late winter / early spring has helped reduce it. Removing the leaves that have the spots helps some and as does removing dead leaves that fall around the plant during the year because they may also harbor the spores.

Here is a link that might be useful: Leaf Spot Management


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