To late for dormant spraying?

Two questions. at what point should I release my mason bees? and since its clearly to late for dormant spray. What should I spray to combat the blacknot and gummious I had on my plum and peaches last year.

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If there are no open flowers and only a teeny bit of green showing at the tips it is still OK.

what should I spray? And the follow up when do I spray to ward off PC?

It depends on what problems you have been having. My default spray is dormant oil plus lime-sulphur. I use copper if I had bacterial spot problems the previous year.

PC is much later, after petal fall. See the spray schedules in the guides category for ideas there -


lime-sulfur does not appear to be available even at the link you recommended.
When I was doing my research I seems this copper fungicide from bonide is a good alternative. Active ingredienat 10% Copper Octanoate. Do you think Saturday or sunday would be a good day to spray?

I hadn’t even considered dormant oil spray until today…so it’ not too late. With the rain it will have to wait a week or two here. Normally March is OK, but this year is probably even earlier than last year. So I better see if the sprayer still works pretty soon!

The Bonide Copper is weak against Peach Leaf Curl.
If Liqui-Cop by Monterey or Liquid Copper Fungicide from Southern AG can be found and used,preferably with a sticker,that should work.Both have 27% Copper diammonia

Useless crap, way too weak to be good for anything but maybe powdery mildew.
Kocide is the very best.

Oops… I fixed the link, Peaceful Valley sells it still. But it is 2.5 gallons.

Agreed on the Bonide copper. I use Kocide when I spray copper.

Me too! They claim the copper ions are released over a longer period of time which helps a lot. It’s available in an organic version too. .

MCE or Metallic Copper Equivalent seems to be the magic number. Kocide 3000 is 30% MCE. Its possible and probably safe to spray lower copper doses even as late as bloom or shuck split on Peaches as suggested by the commercial spray guide but the rate is reduced from around 2.5# MCE per acre to about 0.1# MCE/acre which ain’t much

Edit: Forgot to mention the copper soaps. I believe the Bonide is a copper soap with a MCE of just a little more than 1%. I have never used these products but I suspect they may be helpful for some disease problems if sprayed a couple of times a month as an alternative to constantly spraying synthetic chemical fungicides that we discuss a lot

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Release your Masons when your trees have their first blooms open.

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50f Kocide in hand. Am I clear to spray? For my purpose black knot the insturctions say to apply at bud swell up to early bloom.

But how do I dilute 1.75-3.5lb per Acre down to a 2 gallon sprayer.


@scottfsmith Do the calculations look right

Kocide 1.75lb (.8kg) per acre
Water 400 Gallons (1514L) per acre


= 0.05284 kg/Liter or .44lb/gallon

Nearly a half # per gallon?

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yea, hence why I am reaching out for expertise. The solution might be dividing by 100.

It says 1.75 lb per 400 gallons so that is (1.75/400) lbs per gallon, i.e. .0044 lbs/gallon.

Also see Spray amounts guide where there should be a recommended amount for Kocide amongst other things.

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@jaypeedee has to be right: if 1.75 pounds, or 28 ounces, is correct for 400 gallons, then for 1 gallon it would have to be 28 ounces divided by 400 equals .07 ounces. That’s hard to measure accurately without a triple beam balance or powder scale. But if you do have a trip beam then you need .07 times 28.35 equals very near 2 grams. Just for the heck of it I weighed a teaspoon of corn starch and it was close to 3.7 grams; a teaspoon of table salt was very close to 7 grams.

If Kocide is stable in solution and you could get enough to go into solution you could mix up a concentrate, say 10 grams in 100 ml, or 100 grams in a liter. Then 20 ml of solution would have 2 grams of Kocide in it.

But let’s get somebody else to weigh in; I’m no chemist and it has been a long time since I had to know how to figure this stuff back when I sold chemicals to photographers.

Thanks. I wrecked my only pair at the waterpark a month ago. I am going to blame my glasses and rapid onset Presbyopia for my inability to read and comprehend.

Found the link in @J.D post that gives a solution for Kocide 2000 2tsp/gal @ 1.5lb/A.
Now Kocide 2000 and 3000 have similar % of active ingredients but the pounds per Acre are about double. And if I apply that to the figure for Kocide 3000 I get about I get 4.66 tbs or 1.5Tablespoons or in other words exactly what @scottfsmith put in his Spray amounts guide.

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I just sprayed Kocide 3000 today. Mixed .5 gallon of water with 1 tablespoon of Kocide and .5 tea spoon of Nufilm. Turned out I should’ve mixed a full gallon. I sprayed plums and peaches. I’ll have to mix another .5 gallon some other time for grape vine and pears. Plums and apricots were getting ready to bloom so I’m glad at least part of the spraying is done.

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