Hi, imred! A recent thread discussed this at length. If it doesn't answer your questions, you can resurrect it. Misterbaby.

Here is a link that might be useful: Fruit spray

Mister Baby, you are a real asset to this forum. I need to learn how to post links so I don't have to keep repeating myself.

Whoever runs this forum should post in large letters that you should first search the archives on your topic.

Newcomers just don't realize that and veterans sure do.

Thank you, Harvestman. Here's how to post a link:

1. Pull up the link you wish to post, and right click on your browser's address bar.

2. Left click on copy.

3. Return to 'Post a Follow-Up,' put your cursor on 'Optional Link URL,' right click, and left click on 'paste.'

4. Then, on 'Name of the Link,' type in a descriptive name of your choosing.

5. Done.

I warehouse clippings of interest in 'my clippings.' To see if I've explained this properly, let's pretend that I'm interested in a new pair of pruners. Please go to Misterbaby's 'see my clippings,' pick the right post, and reply here with the link. You may also wish to know how to post a picture. See the link below. Misterbaby.

Here is a link that might be useful: Posting a Pic

Red,

You don't have the most effective products available, but you're not spraying worthless stuff either. Quite frankly, I'm surprised those fungicides aren't working for you. Although brown rot has reported resistance to Topsin M, I would have thought it still effective in a non-commercial setting. Captan is still rated as good for BR, even under commercial pressure. Have you checked your water pH. Captan's half life is only a few minutes at higher pH's. Ziram is a bit weak for BR, but I use it as a rotational partner. The last month before ripening is the most critical time to protect fruit/to get the sprays on. However, early sprays in the season can reduce inoculum. I assume you are destroying all infected fruit/mummies?

If none of the above seems to be your problem, I'd try some stronger materials. The DMI's, Indar and Orbit which are frequently mentioned here are very effective. Pristine is also highly effective.

Thanks olpea, I'm not sure what the ph of my water is. What is the half life of these fungicides in neutral water? What about Imunox? Also hman suggested Monterey fungus fighter, ever use it?
RED

Monterey Fungus Fighter is the same material as Orbit in a home orchard scaled quantity.

Hadn't heard that alkalinity is an issue with Captan as I know it is with Imidan. Usually in areas with alkaline soil, water is also alkaline, I believe. You should definately test your water or if you are on municipal water make some phone calls.

I should have read your post more carefuly, I didn't notice the "sprayed religiously" part. Does that mean within 24 hours after every rain? The DMI's or SI's as I call them (as well as my info sources) don't wash off in rain, which is a huge advantage.

The materials you are using are preventitive (pre-emergent) and must be on trees with the arrival of fungus. The SI's have about 4 days of kick-back, meaning they can stop an infection after it starts. They also don't have to be reapplied during rainless stretches (to control BR), as I understand it, and in my experience.

Actually, I think your materials, besides Capatan are not even used in NY as control for BR. TopM is only recommended for scab control and not BR and Ziram is only listed as a control for PLC.

Hman,

I don't have a Cornell guide but I think the reason they don't list Topsin for BR is due to resistance. Topsin is actually supposed to offer pretty effective BR control to non-resistant populations. The Midwest spray guide rates it as excellent in non-resistant populations. Ziram is rated poor to fair for BR. According to the Midwest guide, Topsin and Ziram are good tank mix partners for BR since they have different modes of action.

Red,

Hman's correct DMI's/SI's are really going to give the best control. They don't wash off and have curative abilities in the early stages of infection. Again Indar and Orbit are going to be your best choices. Orbit also goes by the names Tilt, Bumper, and for a homeowner formulation Montery Fungi Fighter.

Captan is very unstable at higher pH's. However, at neutral pH it is fairly stable, with a half life of about 8 hours. However, with a pH of 8, the half-life is only 10 minutes. (See This pdf link

You may assume your water is neutral, but according to Penn State (See This link ) "A pH of 7.5 to 8.5 is quite common for many waters in the U.S.... Lake Michigan ranges b/t 7.5 and 8.5, while Lake Ontario is b/t 7.9 and 8.3.... City water frequently ranges upward between 9.0 and 9.5 due to water treatment procedures."

Indeed that's what I've found with our water. The annual water report indicates a pH of 9.4. I've also tested it, and indeed it tests around 9.4. At such a pH the half-life of Captan is just a few minutes.

Lastly, I posted a link below to a U.C. Davis guide on fungicides. It's an older spray guide (2005) but it discusses a lot of the pesticides referred to in this thread. It also discusses the mode of action. (See link below)

Here is a link that might be useful: Timing and Efficacy of Fungicides - U.C. Davis

Olpea, thanks for that link about chemical stability and ph level. I never even considered such a possibility. As far as the combination I am using I was using
Captan and Ziram alternately in 2008 and lost most all my stone fruit. They were both reccommended in the spray guide. Then last winter I was trying to find info and I found a chart that showed both only had Poor to
fair suppression of BR. So I started mixing with Topsin which was reccommended. I did get about 25 to 65% crop accdording to the tree. I'm going to try MFF this yr. Hope that will do it. Hman, I was pretty faithful with 7 to 10 day spray intervals but with my other work I might have missed sprays directly after a rain as we had quite a lot last yr. Thanks for the info, I really appreciate it.
RED

I thought I had thanked Olpea here for his excellent referrences, but noticed I didn't (I did send him a note). I have gotten a lot of useful info from him on this forum and the link about the risks of alkalinity is particularly useful to me. Anyway I wanted to chime in on giving him credit.

Imred, I believe your BR problems will subside with the addition of the right SI in your program. I'd be inclined not to rotate but to tank mix another fungicide if you're worried about resistance development- at least until I got the BR under control. Once you've gotten control for a season you can begin to experiment with how little spraying you can get away with.

"Mister Baby, you are a real asset to this forum. I need to learn how to post links so I don't have to keep repeating myself."

"Whoever runs this forum should post in large letters that you should first search the archives on your topic.
Newcomers just don't realize that and veterans sure do."

I can't help the OP.

But will say....

SAVE your replies that keep coming up in text files so it is no big deal to cut and paste the answer in.

It is a pain in the ass to search through tons of threads looking for a simple answer just to not find what you wanted.

Use cut and past to save your time!

thanks hman, I'll use MFF this yr. and hopefully that will let me get control of the BR.
RED

Thanks folks!

What do DMI and SI stand for? I didn't see the full names listed above.

They are used interchangeably. The actual full term is "Sterol Demethylation Inhibitor". For brevity, it was shortened to Demethylation Inhibitor (DMI) and further shortened to Sterol Inhibitor (SI).

This is how I understand it (Mind you, I'm not a biologist, even less a plant biologist.)

Everyone is familiar with steroids. Two common ones are testosterone and estrogen. Testosterone is what makes little boys jump off the top bunk of the bed while wearing Superman underwear, and causes men to make completely irrational decisions. Estrogen is what makes those nice curvy lines in women.

However, there are actually lots of steroids in biological life. Cholesterol is a steriod (Notice the word sterol in cholesterol.) Sterol is a specific type of steroid. Demethylase is a specific type of sterol that is necessary in fungi. The DMI's inhibit demethylase. How they do that I don't know. Perhaps they block the production, or perhaps they block the pathways (delivery route).

Thanks olpea!

Now I can hit "print".