Last year I had very bad case of brown rot blossom blight on apricots. I want to do preventive spray this year, but not sure if I understand the label right. It reads:
Apricot and nectarine (Brown rot blossom blight, Brown rot, Powdery mildew and Shothole control): Mix ½ fl oz …Apply at early red bud stage (the tips of the petals are visible and the flowers are still closed) before infection occurs.
The problem is, I am not sure if red bud stage is actually only applicable to nectarine and for apricots it is a first white stage. Because right now buds look red, but petals are not visible, the petals on my apricots are white. So should I apply the Immunox spray at this stage
or at this stage 
?
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From the things I’ve read, Immunox is not effective on brown rot shoot blight. I’ve had what I think is pretty bad brown rot shoot blight on my nanking cherries, check out this thread about that:
I did spray some copper on them this weekend since I had mixed a tank for something else, but my main plan is to spray Indar during bloom. In some of the papers linked in that thread, two treatments are recommended with fungicides that have different modes of action. I need to get ahold of something else to spray for it in addition to Indar. I have a small bottle of Indar which I got via a group buy here a couple months ago.
Every year there was a problem with Blossom Blight and my bush Cherries.Immunox was used for the first time last Spring and it really helped.
I probably waited until there was some color seen,like in the second photo.
This time,Captan is being tried,because of not being a systemic.
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So far i try to avoid Indar. But thanks!
Thanks!
Galina,
Captan needs acidic water. Do you know what the ph of your city water is?
I read that for regular food grade vinegar, you need 1-2 TBSP of vinegar per gallon of water.
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Daconil/chlorothalonyl is recommended for blossom blight, I suspect it can even be sprayed on open blossoms.
I think Captain is bad for apricots, read the label carefully.
The label on my Captan 80 WDG says it can be use on Apricots.
APRICOTS
DISEASE
Brown rot (twig blight)
Jacket rot
APPLICATION RATE
(Lbs. Product/Acre
1.87 to 3.12
DIRECTIONS
Apply in 20 to 250 gallons of water using ground equipment or in 10 to 20 gallons of water by air.
Apply in red bud, bloom, and 75% petal fall sprays.
To reduce the potential for disease resistance development to other fungicides having a similar spectrum,
use the lower rate in tank mixtures.
RESTRICTIONS:
• Do not apply more than 15.6 pounds of CAPTAN 80 WDG per acre per crop cycle.
• May be applied up to day of harvest.
• REI is 24 hours.
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Now I remember where I saw the warning; check the link below from University of California:
http://ipm.ucanr.edu/PMG/r5301811.html
Excerpt: “ Caution: Never apply sulfur to apricot trees or captan to apricot fruit.”
That’s interesting that it states apricot fruit.
I am not using Captan on apricots, only on strawberries so far and i add vinegar
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Where did Captan come from into this post? I am asking about Immunox
I’m the one.
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A couple of years ago I sprayed my apricot tree with Captan while the fruits were olive size, and I lost ~50% of the fruits within a week of spraying. They started developing pale brown discoloration, wrinkles and fell off. That was after thinning, so it was not a matter of too much fruit on the tree. If I remember correctly, the foliage was affected too, but obviously the tree could produce new leaves in the middle of the season, but cannot replace lost fruits. That was before I read the UC guidance…
Was the prevention against Brown Rot?
I’m definitely only spraying during bloom.
The Captan label says nothing about spraying the fruit, as the poster was asking about blossom blight.
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You are right @jaypeedee, I confused the UC guidance with the product label. However, based on my previous experience, I would not use captain on apricot trees again. If you look at the chemical structure of Captan, you’ll find it has a sulfur atom, and sulfur is another pesticide that’s contraindicated for apricot trees. Perhaps captan’s sulfur atom is somewhat freed after spraying and does similar harm to that of elemental sulfur.
Yes, it was for BR and other fungal diseases in general. I used the same spray mix for all my stone fruits. Now I replaced captain with infuse and other fungicides that are safer on all my crops.
Galina,
Immunox (myclobutanil) may not be as effective as Indar but it will help. Another product is Bonide Infuse (propiconazole). It is supposed to work quite well on blossom blight.
Unfortunately, these 3 products, Immunox, Infuse and Indar, are in the same chemical group (group 3), repeated use of them over time could create resistance.
However, if you spray a few trees a couple of times a year, it may take a long while before resistance could build up. The concern is more about commercial use with repeated, large scale spraying I believe.
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