I found another article about it.
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7481.html
Now that I’m thinking about this,there are other options,such as a Chlorothalonil product,like Daconil.
Honestly, now you are opening a whole new area of discussion that I’d love to explore with others here. And that is the question of why I am so married to the idea of copper and oil for a late winter treatment. I’ve always done it and lots of people recommend it, but I really don’t know if it is worthwhile compared to other things. Specifically, I use both Captan AND miclobutanil during the growing season. Both are fungicides. So do I really need a different one for dormant/early bud swell spray? Could I just use the Captan or Miclobutanil as my first dormant spray? I feel like Copper does better on my peach leaf curl and that is based on some minor experience but not a thorough testing or scientific method, so I certainly could be wrong.
So what say everyone. Is copper/oil really much better than if I used Captan or Miclo right before bud break?
It probably does matter,as what the target is.I’m trying Captan,for the first time,against Brown Rot Blossom Blight on my bush Cherries and spraying some other Prunus just in case.But I haven’t read of it being use specifically for PLC.
Myclobutanil (Immunox) was a new one,used last year and it helped a lot,reducing BRBB,but a decision was made to switch,because of being a systemic and I’ve read that a resistance can be built up,unlike Captan.
I think so. Different fungicides control different types of fugi. It happens that copper is better at control the fugi that causes the PLC.
About using blue stone alone in spray. My understanding is that you can as long as you use the correct amount. I mixed Bordeaux myself every year. As far as I know , adding lime to the copper solution is to make the solution milder to the tree also stick better. But if a mature and dormant tree should be able to handle the copper alone. Well, this just my understanding from what I read, I have never spray blue stone solution alone. I always mixed with lime according the formula
here’s a list of leaf curl controls in the PNW, some alternatives are lime sulfur and ziram
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I am using Liquid Copper Fungicide Conc - Bonide. It is supposed to be a substitute for Bordeaux spray. I also use chlorothalonil, and it works great.
My two biggest offenders are plc and fire blight. I spray only twice a year, at leaf drop and before bloom, with copper and dormant oil. I haven’t had a problem since I started spraying. I sometimes skip the spray at leaf drop if blight wasn’t a problem that year. I’m happy that I get away with very minimal spraying.
Kevin,
It seems copper sulfate may not be as effective and you may need to use more of it by volume. This old thread has some good info.
Generic Copper Spray - #6 by J.D.
I have heard that chlorothalonil can be used against PLC. This spring will be the first time I will try using lime sulfur for PLC. If it is effective, I will switch from copper to it.
Thanks Tippy. I’m curious why you are trying to get away from copper? Is it fear of the buildup in the soil under the tree? I ask because its always been really effective for me so I wonder why you’d switch?
You should be happy you can get by with just 2 sprays. I’m certainly jealous of your southern CA climate! Here in the southeast, I have to contend with PLC, fire blight (in extreme- occasionally to the death of apple and pear trees), brown rot, Black rot (on grapes), powdery mildew, blossom rot, pear rust, cedar apple rust, and more!!! And far worse than all of that is the unbelievable insect pressure- especially OFM and PC and peach borers among others. I have to spray for one or more of these diseases and pests about every 10 days or I can loose my entire crop (especially with stone fruit) in just a day or two. So I do hope you know how different things are for us growers on the other end of the country and how lucky you really are. I’d like to be organic but it just isn’t practical here.
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Yup. Concern about build up in soil over time. I usually spray it twice a year in late fall and before bud break. I
I sprayed last fall. Will switch to lime sulfur this spring. It will help wit pear blister mites, too.
Quick question - for these dormant fungicide sprays - do you guys spray any time of day with any amount of sunlight or do you do it only in early morning or evening in non-direct sun like you would if the trees were leafed-out?
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I wasn’t trying to rub it in or make it sound like you can get away with doing less. Sorry if that came out badly. My intention to the OP was targeting specific major offenders and whether your copper product can deal with them. I don’t get PC in my area, but I do use pheromones traps for the OFM. I also wonder if my neighbors’ fields of sunflowers provide some biological control for OFM.
I occasionally have to spot spray with spinosad, myclobutanil, and chlorothalonil during the active growing season. I don’t consider myself an organic gardener at all. I just do the minimum for my area if I can get away with it.
I usually do evenings when I don’t expect rain in the next several days. No idea if it’s better or worse, but I pick evenings because it’ll have longer time drying before my kids play in the yard again.
Thanks for saying that Martin, and I didn’t take it that way. I was being honest and sincere in saying I was jealous of your climate and lower pest pressures, as well as the fact you can grow many things I can’t!!! But the grass is always greener on the other side…I’m sure there are things I can grow that you can’t. But no matter the conditions, growing fruit is challenging and I’m sure you have issues there too. But its really nice of you to clarify that you weren’t being condescending of my use of chemicals-even though I didn’t take it that way.
@TrilobaTracker - for me, I’ve honestly never paid any attention to the time of day/sunlight for my dormant sprays and never noticed a problem or need to do so. That doesn’t mean I shouldn’t -I’m no expert- just letting you know my personal experience. To be honest, though, I also have sprayed most of my sprays in mid day sun even when trees are leafed out. I’ve read that it can be problematic but I’ve only felt like it was a problem one or two times and even then it was because I was trying to use a weak copper spray after leaf-out which is not wise anyway. That being said, its usually late day when i spray just because I tend to do other things first and spray late.
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If it is during dormancy, it does not matter much like Kevin said. I like to spray early so it will dry out during the day. I always try to avoid spraying if rain is forecast during the next 24 hours.
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Thanks for the feedback y’all. I agree it doesn’t seem like full sun/midday dormant spraying would be an issue but wanted to play it safe.
I have some of that root killer that plumbers use and i just mix some crystals of it in a spray bottle with some water and spritz away. I’d have to look up the amounts i use. Never get peach leaf curl.
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That is the Cu(So4), just in less pure form. You can use it mix with lime to make Bordeaux spray
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