Combatting brown rot


#21

Funny last year I didn’t have any spot, but had a form that hits tomatoes. I had some spot on tomatoes.Just a few, not all of them. A bacterial spot too. Keeping area clean seems to help. I also think that one of the sprays helped. The oil-lime-sulfur doramant spray I think will kill any spores fungal or bacterial on the tree.It can be used as a treatment too during the growing season. The super strong dormant spray with oil to hold it on the tree really is what I think eliminated it.When trees are leafed out you can use 4 ts per gallon. In the dormant spray you use a whopping 4 oz of lime-sulfur, this strong dose kills all spores and insects or insect eggs too, good stuff! It would kill all leaves too if tree had leaves, dormant only!


#22

Drew,

I’ve noticed, like brown rot, bac. spot is highly dependent on environmental conditions. The big issue here is wind. Here at the house, it’s not near as windy as at the farm. The farm is located in a natural wind channel with no wind breaks. The wind constantly abrades the leaves exposing them to infection. One other issue is the farm gets sprayed w/ an airblast, which produces very high velocity wind. The trees sway like they’re in a hurricane. I spray the house trees w/ a wand, which produces a relatively gentle spray.

I also get some bac. spot here at the house, though not as bad. I use oxytet to control it. I haven’t tried the lime sulfur.

I’m a bit surprised you get such good control w/ it. I’ve always read it takes continual protection to control bac. spot (as I recall from memory oxytet is labeled for 9 sprays). This has been my experience at the house. 8 or 9 sprays completely controls it for a very susc. variety, regardless of the the amount of rain. I’ve also tried 1/2 the amount of sprays, which doesn’t provide near the control.

I don’t mind spraying the antibiotic at the house, where I only have a few peach trees which need it. I have too many trees at the farm to selectively spray, so I plan to remove susc. varieties there.


#23

Has anyone tried these fruit bags that Clemson has been developing and evaluating?
www.clemson.edu/extension/horticulture/fruit_vegetable/peach/diseases/peachbags.html
Sounds like it is aimed at eliminating summer fungicide/insecticide cover sprays but I think they still did fungicide sprays around bloom and just before bagging.


#24

Fantastic. Just sent in an order request. Similar bags have been used in Japan as well. But they were never this reasonable in price. Thanks so much!


#25

Whoo boy. My neighbors are really going to be shaking their heads now. The back of my lot borders a busy residential road. Passersby have a clear view of most of my fruit trees and veggie gardens, but the flower garden areas are mostly obscured. I already keep most of the veggies covered with insect netting and/or frost cloth unless something is blooming that needs to be pollinated. They might really think I’ve lost it when they see little bags hanging throughout the trees. The squirrels will probably wonder why I went to the effort to pack their lunches for them.

Even if I bag, I think I’ll probably still wind up spraying because my trees had gotten to the point where I was losing everything to brown rot and curculios until you guys put me on a proper schedule.


#26

That’s an interesting observation, and could explain why I got it too. I know we at times can have high winds.

Well I’m not sure I do? Or did, just trying to figure out why I went from a fairly bad infection rate to no sign of it? Unsure really? The only other product that could have helped was Actinovate which I also used, It could also be that what I had was shot hole, or Captan damage and not bacterial spot, although it sure looked most like Bacterial Spot. Also I had it 2 years on a row, but not last year.


#27

I don’t think the wind is anything but helpful for most fungus because it helps remove dew and generally airs things out. Brown rot tends to start in the fruit and move to the leaves and then into the wood, so I don’t know if abrasion is an issue and it’s not something I’ve noticed.

What I know is extremely helpful is eastern exposure. Even with tomatoes it is crucial here to evaporate the dew as quickly as possible. I purposely locate brown rot susceptible trees on parts of my property that get earliest sun.


#28

Alan,

I’m not sure if you were responding to me. If not I apologize. Perhaps you were just clarifying the beneficial relationship of brown rot and wind, for the benefit of the thread. I mentioned abrasion, so I wondered if you were specifically responding to me.

I completely agree w/ your conclusion of wind and brown rot. Wind is definitely helps dry things out and reduces infection time for brown rot.

Where I think wind is detrimental is for bac. spot. The minor abrasion of the leaves increases entry points for bac. spot. On sandy soils, it’s reported wind contributes even more to bac. spot infection because the leaves are sort of “sand blasted” creating lots of minute entry points for infection. We don’t have sandy soil here, but I see some abrasion in the foliage at the farm, along with some pretty “ragged” foliage from the wind. I think this results in more fruit infection because the colonization of the bacteria in the leaves washes more bacteria down on the fruit during rain.

Here is one small excerpt about the relationship:

“Bacterial spot is favored by hot, dewy, wet conditions, and windy, sandy
sites. Spread and entry of the bacterial spot pathogen into plants is
favored by abrasions and nicks caused by blowing sand, especially common
on outside peach rows next to dirt roads. Spraying trees when foliage
is wet from rain or dew may help to spread bacterial spot.”


#29

Yes, I just wanted to make sure there was no confusion about the wind being an issue for brown rot. I learned about the abrasion issue with BSpt from you several months ago. I know much more about BR than BS as I’ve been dealing with the former for decades at multiple sites but I’ve just begun growing BS susceptible species.

My orchard is protected from wind so I’m hoping the BS won’t be too bad here.


#30

Barry I used the Chinese bags last year on apples and peaches; I would say 50% made it. The rest the squirrels managed to discover and rip the bags.
For brown rot, I use Clearys Wp repackaged by Southern Ag …Thiomyl Ornamental Systemic Fungicide 2oz Gen Clearys


#31

The word Ornamental in that name made it sound scary to me. Is it approved as safe for use on edibles?

Squirrels are smarter than they get credited. Once they find goodies in one bag, I doubt if it takes them long to figure out that bags = treats.


#32

Not to mention the word “systemic”. I thought the same thing Muddy, but it turns out, this product actually IS listed for fruit trees. In fact, a couple university guidelines I came across actually recommended it’s use on pears since Captan is no longer listed for them.
Captan is cheaper though and more effective against most fungal issues.


#33

Yes it is, but it says nothing about use for brown rot. What scares is that it is a systemic. OK I found a label for TCleary’s 3336 Fungicide, which is what this is, and it says do not apply on fruit trees after fruit set. So this is not going to work for brown rot without poisoning yourself. Not labeled for use against brown rot. It also says this “Do not use fruit from treated crabapple or pear trees for food purposes.” I would not use this product at all.
http://www.spsonline.com/sps/sites/default/files/imagefield_thumbs/3336.pdf


#34

Drew your link actually does mention it’s use for brown rot under “Foliar Application” (12-16 ozs. per 100 gal.), but like you say, the non permitted use after fruit set pretty much kills it.

I have seen Thiophanate Methyl listed in very many efficacy charts over the years, and they were always dealing with tree fruit, so this might be another issue with listing costs etc. I think in those cases though, it was being mentioned primarily as an additive to other base sprays (I think). The fact that they bother to mention you shouldn’t eat fruit treated with it though kinda makes me leary. The advantages I see with this product are efficacy in areas where many base sprays like Captan may lack. It is also available in reasonable quantities and at reasonable cost.
Those things aside, and when all things are considered, Captan + Sulfur or Captan + Myclo or both are impossible to beat imo for the BYO.
While Captan is effective for BR it’s apparently lacking a bit, a sulfur addition helps, but according to efficacy charts the addition of Topsin M is the bomb. It’s fairly cheap at less than $60 for 5 lbs, from KPS.


#35

The word systemc doesn’t really bother me as that is the nature of SI fungicides such as Rally and Indar, which penetrate the surface of fruit and leaves, but doesn’t move from there (there should be a separate word when systemc means moving freely throughout the entire plant).

People that are warry of a little pesticide residue would prefer Captan over Indar or MFF because it will wash off with a bit of effort- but that’s why it needs to be re-applied after heavy rain. It also lacks the kick-back of the SI fungicides which I believe is crucial if you want to vastly reduce the number of sprays.

I think using thiomyl is a bad idea and I wouldn’t even consider using something that hasn’t proven to be as effective against brown rot as something like Captan which is readily available, cheap, and not terribly poisonous.


#36

Their isn’t a better word than systemic, you just defined what it means.


#37

Topsin M is a brand name of Thiophanate Methyl which is the chemical mentioned in the picture. On a scale of 1-5, it rates a 4 on brown rot in my area with a 1 day PHI. Captan rates a 3 on brown rot with a 0 day PHI. Rally (myclobutanil) ranks a 3 also. Indar and Pristine both rank 5.

Not sure what the label restrictions are on the chemical in the picture


#38

Blue…what is the application rate of Indar and Pristine to achieve the 5 rating? Does Indar and/or Pristine require a mixing partner to achieve the 5 rating? I was aware of the high efficacy of both Indar and Pristine as both were listed on all the charts I looked at, but since neither are suitable for BYO due to purchase quantities and cost as well as storage life, I didn’t mention them. I was also under the understanding that high app rates (even beyond current labels) were now required to achieve their initial efficacy ratings and also a base mixing partner like Captan were required. Do you combine them with anything and if so what chemical?
I didn’t know that Topsin was in fact, Thiomyl, but I did know Thiomyl was Thiophanate Methyl. I did notice however that it seemed a good mixing partner for Captan, not based on efficacy chart suggestions, but rather just looking at their respective fungal controls. So that makes total sense to me.
My suggestion of the combo being “the bomb” came from a few sources with Clemson being the most notable. It seems the combo excels in it’s ability to overcome resistance issues, even though Topsin does by itself have resistance problems (high). Somehow the combo with Captan alleviates this moreso than the combinations of Captan and Pristine or Indar it seems (both medium - high).

The benefits of Topsin to the BYO as I see it, is that it’s WP or WDG and the purchase quantities reasonable and cost is low. I won’t bother with any of it personally until Captan shows that it can’t perform adequate control as a stand alone base spray with combos of sulfur and/or myclobutanil. If I get into peaches again, I suspect I might have to do something though. My buddy here has real bad issues some years with BR on his peaches and plums, but last season he sprayed the same Captan as me (sometimes combined with myclo) and according to him, had no issues. I don’t remember though what he used to use for fungal control. He also used to leave mummies hanging though also. He stopped doing that at my suggestion and that might have had more to do with his success last year than anything he sprayed.

Drew posted a link to the label and like Drew said, following the label of the Thiomyl as pictured here in the thread would render it totally useless for fruit growing, or at the very least, certainly for BR control.


#39

Drew, I think what Alan is saying is that the word “systemic” is also used for those chemicals which are applied as soil drenches or direct injection. So in that method the chemicals are taken up by the roots and distributed throughout all living parts of the tree or plant, including the fruit. Those types are not labeled for fruit trees, only ornamentals etc. I think most people think of this when they hear the word “systemic”. I know it’s always the first thing I think of, especially when they are coupled with the word “ornamental”.
The SI class stuff also uses the same word, though the mode is different and less dangerous (apparently).

I agree with Alan, there should be other verbage used to distinguish these two different things. SI’s are not at all what I’d define as being systemic, and I’m even dubious of their claims of tissue penetration. I think, for the most part, they are surface sprays like everything else.


#40

OK, thanks makes sense now and I agree.

Mancozeb is one systemic approved for edibles. It’s an organic acid.

I mentioned this again though I use pyraclostrobin with boscalid which are Quinone outside inhibitors and alternate with propiconazole which is a Demethylation inhibitor. And these are available for backyard use. I’m finding the approach effective.