Spray recommendation for blooming stone fruit trees

andrew_swmo(6 SW MO)April 4, 2013

My plum and apricot trees are in bloom. Peaches and European plums will soon follow. The rain has been on and off so I am kind of confused regarding what to spray and how often. I used copper sulfate and dormant oil about two weeks ago on all my stone fruits. I also used Daconil on the blooming apricots about four days ago. The plums were in the early stages of bloom and got sprayed with Daconil and Captan.

I wonder if I should also use copper sulfate and how often I should spray if there is rain while the trees are blooming. I always add a spreader sticker in the mix. Thank you.

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Spray copper before bloom. Once blooming, you have to wait until all pedals drop before spraying again so you don't kill all the bees. I use spectracide for fruit trees every 2 weeks and stop 3 weeks before harvest with very good results.

    Bookmark   April 4, 2013 at 4:05PM
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olpea(zone 6 KS)


Actually copper is fairly non-toxic to bees. It's used on apples and pears during bloom to control fireblight. The biggest problem with using copper at bloom is that it can be quite phytotoxic on some blooms (and some foliage too).


Here are my thoughts on your spray program so far.

First, I don't spray stone fruits will oil much at all. I didn't spray any stone fruit with oil this year which is generally my practice. I save my oil for pears and sometimes apples. Some people use oil as a sticker for their copper (as I have done) but you mentioned you are already using a sticker, so the oil would be superfluous in that case. I rarely have aphids, mites, or scale on stone fruit, so oil is not needed here much for prunus.

Your dormant copper spray is a good call. It's necessary to combat leaf curl and can be helpful to control bacterial spot on peaches and your other stone fruits. It may have been a wee bit too late in the application for leaf curl but may be OK this year.

Daconil on your blooming apricot is primarily to control blossom blast, caused by the same fungus that causes brown rot on the fruit. Sometimes I spray blooms for blossom blast and sometimes not. It really depends on how wet the spring is and how much rotten fruit is on the ground from last year. This year spring has been pretty dry and I don't plan to spray for blossom blast. I rarely have a problem with it.

Daconil can be helpful on plums sprayed this time of the year to prevent black knot. There would be no reason to spray your early blooming plums with both Daconil and Captan. They are both broad spectrum fungicides with multi-site activity. Both control blossom blight and scab so it's redundant to use both.

I think you're covered on the fungicides for now on your stone fruit, unless we start to get a tremendous amount of rain, or you have some problems with black knot on your euro plums. Beyond that, I wouldn't look to start spraying anything else until shuck split, when the curculio season gets rolling.

    Bookmark   April 4, 2013 at 10:42PM
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andrew_swmo(6 SW MO)

Thanks Biomed and olpea. The last ten days have been fairly wet in my area although I am not far away from you olpea. We are also expecting more rain next week. I've sprayed copper in November or December so I hope that would take care of leaf curl.

I lost a young peach tree (Champion) due to leaf spots two years ago after a rainy spring. I also think my Stanley plum had leaf spots last year. Mites have also been a problem for me as I used to use sevin before knowing that it kills their natural enemies. I wonder what insecticide does not cause flare of mites population. How about Triazicide once and Done?

    Bookmark   April 5, 2013 at 9:55AM
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olpea(zone 6 KS)

"I lost a young peach tree (Champion) due to leaf spots two years ago after a rainy spring."

hmmmm, I've never seen a peach tree die from leaf spots.

Bacterial spot and leaf curl (which also causes red "spots") will both weaken a tree as the tree has to replace the defoliation from these diseases, but I would expect any decline to a somewhat drawn out process. At least that's what I see around here.

Most of what causes peach trees to die rapidly here is too much water on the roots and allowing sod to grow under the tree which contributes to the stress.

I don't think most people realize just how much peaches hate soggy soil (even for a short period during the growing season). The whole thing is really counter-intuitive. People see oaks, maples, Bradford pears, cedars, apples, hedge, etc. etc. growing fine nearby, even thriving. Naturally they see these trees in their neighborhood and conclude peach trees should do just as well. But they won't, mostly as a result of the heavy soil and prolonged spring and early summer rains. If you ever see water sitting on top of the soil (even while it's raining) that's too much water for a peach.

The largest blueberry farm in MO is not far from me. The owner mentions on his website that years ago they started out in peaches and lost every one of them, and so switched to blueberries. I can guarantee he lost those trees because of too much water. My farm is only three miles from his and I know the soil.

I lost lots of peach trees before I started planting in raised plantings. Since then I haven't lost a single peach tree except for trying dumb things like planting in a mounds of almost pure woodchips.

I still see the effects of planting peaches on flat soil. Neighbors all around me still plant peach trees which generally die fairly rapidly unless they are planted on a natural rise. The peach trees planted on a natural rise aren't what I'd call healthy because they get no care, but they don't die, or if they do it's a very slow decline.

Regarding mites, I've only had problems on apple, pear and green beans. Triazicide will probably cause mite flares as fast as Sevin. Both are very hard on mite predators, but unfortunately not very hard on the mites themselves.

If you are having problems with mites on your pomes, I would recommend adding a little oil in with the Triazicide. Don't exceed 1% oil in the summer time and don't spray oil when it's really hot, or you'll risk burning the foliage. I've used 1% oil once or twice during the growing season to keep mites in check and it's worked pretty good for me.

    Bookmark   April 5, 2013 at 2:04PM
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andrew_swmo(6 SW MO)

Thank you, olpea. You nailed it. The tree that died was in heavy soil.

Is there a simple calculation to know how much oil to use per gallon of water to get 1% concentration? I am thinking if the bottle has 10% active ingredients of oi, then 1 unit of oil per 10 unites of water gives 1% concentration.

    Bookmark   April 5, 2013 at 7:24PM
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andrew_swmo(6 SW MO)

I read once not to mix copper sulfate with oil. Does anybody know if this information is accurate? Thanks.

    Bookmark   April 5, 2013 at 7:28PM
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olpea(zone 6 KS)


Oil is not like other pesticides which have a certain amount active ingredient. All the oil I've seen is simply pure oil (about 98%). It does have a small amount of emulsifier, but other than that it should be just oil. So to get a 1% solution, you'd use about 1.25 oz. of oil per gal. of water.

You wouldn't want to mix copper sulfate with oil during the growing season because of phytotoxicity to the foliage. In fact I wouldn't mix any formulation of copper with oil during the growing season. Copper formulations in general tend to be phytotoxic and carry all kinds of warnings when used during the growing season (don't mix with oil, don't mix with captan, don't use with acidified water, etc.) Anything that increases the penetration the copper into leaf tissues increases the chance of phototoxicity.

All that said, I'm fairly certain a tank mix of copper sulfate and oil would be safe to use during the dormant season. I can't imagine it would cause problems, but check the label to make sure. I've never mixed copper sulfate with oil, but have mixed copper hydroxide with oil during the dormant season with no problems whatever. Again this is in the dormant season I'm referring too, not delayed dormant or the regular growing season.

    Bookmark   April 5, 2013 at 8:18PM
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andrew_swmo(6 SW MO)

Thank you very much olpea. Your posts always contain valuable information and I've learned a lot from reading them. The next peach tree I plant will go on a mound. I may ask you for recommendation when it is time for a new peach tree.

I planted a Castleton/Empress 2 by 1 European plum in place of the dead peach tree about two weeks ago. I know that plums can tolerate heavy soil. I wonder though if you would recommend that I dig the tree out and mix 1/3 sand and 1/3 compost with the heavy soil or raising the soil a little? Thank you.

    Bookmark   April 6, 2013 at 8:43AM
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Where did you get Castelton and Empress, 2 in 1 from, please? I've been considering Castleton for some time now. If I could get both, it'll be even better.

Totally agree with your opinion about Olpea's posts. Olpea also explains things likes a good teacher does, easy to follow and understand.

    Bookmark   April 6, 2013 at 9:28AM
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drew51 SE MI Z5b/6a

OK, I would like to know what would be a good sticking agent for copper? I'm not even sure what form of copper I have? I have a bottle of copper fungicide by bonide.
Here my trees are about to break bud, but not yet. The last night of freezing temperatures was 2 days ago. No trees have any foliage yet.
MSU suggests with cherries to use copper after spring and fall pruning, so it might not be harmful to cherry tree foliage? Maybe they meant after leaf drop? Any thoughts?

    Bookmark   April 6, 2013 at 9:48AM
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andrew_swmo(6 SW MO)

Mamuang, I got the 2 by 1 from Cummins Nursery. I do not think that they still have the Castleton/Empress 2 by 1. I placed my order last December and that was a little late to get what I really wanted. They still have Castleton.

    Bookmark   April 6, 2013 at 6:27PM
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olpea(zone 6 KS)

Thanks for the nice comments Andrew and Mamuang.

Regarding the new plum, I would go ahead and leave it in the hole Andrew. I definitely wouldn't amend the planting hole without building a mound.

You are quite correct plums will tolerate much poorer drainage than peach and will grow in all but the wettest spots. I have planted plums in flat ground and plums in mounds. The ones in mounds clearly do better, but that may be partially due to the mounds having looser soil, which makes it easier for the roots to spread.

I have had more difficulty getting good growth on plums planted in the ground, so you might try fertilizing a little the first season or two to size the tree up. I plan on using a little fertilizer on the plums I planted this spring to give them a little boost. My new plums are all planted in flat ground.

"OK, I would like to know what would be a good sticking agent for copper?


I use Latron B1956 spreader/sticker. I don't know that it's any better than any other spreader/sticker, but I'm used to it and know the mixing dosage in my head. Actually it's no longer manufactured, but when I ran out of my last gallon, I was able to find another on Ebay.

Copper is not always harmful to foliage. I didn't mean to leave that impression. It can have the potential to spot or burn foliage. Because of this it's generally advised to use lower application rates of copper in the growing season vs. the dormant season.

Understand that MSU's advice regarding copper on cherry is for tart cherry only. Coppers have a high potential for foliage injury on sweet cherries.

This post was edited by olpea on Sat, Apr 6, 13 at 21:02

    Bookmark   April 6, 2013 at 9:00PM
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Thanks for the info. I am done with ordering for this spring planting.

If Cummins offers 2 in 1 (with Castleton) again for next spring. I will order it this fall. I am running out of space but still want to plant persimmon, euro plum and other things!!! It's addictive.

    Bookmark   April 6, 2013 at 9:20PM
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bob_z6(6b/7a SW CT)

I also bought a 2 in 1 plum from Cummins (Castleton & Seneca). Here's a pic- each stem is fairly thin, but the root system was quite large.

One thing to keep in mind is that there is a $20 extra cost for the multi-grafts. It is reasonable- but they haven't gotten around to adding it to their prices page (their first year selling them maybe?).

    Bookmark   April 6, 2013 at 11:01PM
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Thanks, Bob, for the warning. I've ordered from Cummins before. Its tree are excellent but also rather pricey.

    Bookmark   April 7, 2013 at 8:52AM
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