Should I wait for leaf drop before treating for peach leaf curl?

The attached photo shows three nectarines and one Nectaplum growing close together (a la backyard orchard culture). I was told to give the first of three treatments for PLC at the beginning of December, but at that time all 4 trees still had substantial leaf cover (Due to the warm fall), so I thought I should wait. Now, halfway through December, the three nectarines are mostly bare, but the Nectaplum is still covered in leaves. My questions are:

Should I wait until all the trees are bare before spraying any of them?
Should I go ahead and spray only the trees that are bare?
Should I spray the nectaplum with it’s leaves still on?
Should I pull the leaves off the nectaplum and then spray it?

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Wait till it is almost time for bud break to spray. It will only take this spray to eliminate it. After bud break is too late. Peach leaf curl was the first fungus I had to learn about. Be hopeful that you do not have brown rot next.

Thanks, Robert. I’ve been told by my local nursery to spray three times (beginning of Dec, Jan, and Feb), due to the wet nature of Northern California winters, so I’m reluctant to follow your advice.

Spraying more is always best because you are also spraying for other problems. It is pretty wet here as well. I spray one time for peach leaf curl which kills it, then the rest of my sprays are for other problems. Spraying more times to kill it will never hurt anything but your wallet, but I have managed to control it in one spray. Trust me that’s the easier of the problems to control. If it is wet there then you have of good chance of brown rot. I am just learning to control that myself and it is not as easy. I have close to 50 stone fruit trees and have lost entire crops to that stuff. The good people on this forum have schooled me though and hopefully this upcoming year will be better.
Enter peach leaf curl in the search box and you will find a vast array of information to control it.

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In researching the topic I learned that the most effective means for controlling PLC were taken off the market several years ago. Since the currently available treatments are not very effective most sites recommend treating 2 or 3 times during the dormant season. I would like to follow that advice.

Could someone please advise me as to which option is best:
Should I wait until all the trees are bare before spraying any of them?
Should I go ahead and spray only the trees that are bare?
Should I spray the nectaplum with it’s leaves still on?
Should I pull the leaves off the nectaplum and then spray it?

Where are you in zone 9?

Here is discussion on treatments of PLC. Peach Leaf curl.

I’m in zone 8b southern Oregon and I have to deal with leaf curl yearly. I’d wait for the leaves to fall off the last tree and then hit it with copper then and then again with copper and dormant oil (not for the curl but for overwintering aphids etc) before the buds open up.

I’m in Menlo Park, CA. This is my first season with these trees (planted bare root, last winter), so I don’t really know when they should normally be loosing their leaves, but the local nursery recommends spraying once a month for three months, beginning Dec 1st, so I’m guessing they should normally be bare by now.

My one year old peach tree (San Jose, 9B) lost 60-70% of the leaves last week. I just ran my fingers through the branches and the rest fell down. I removed the leaves on the ground and any mummified fruit and sprayed them with @JoeReal’s Italian dressing. I see people in ultra-low chill areas strip the leaves to improve their chill hours, so I am guessing it should be ok to strip the leaves of your nectaplum and spray all the trees. My challenge was finding the recommended half a day window of no rain to spray the tree. Luckily there was a break last weekend.

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Just my opinion. Once the peach leaf curl is on the tree there is no benefit to spraying the leaves once they are out. The sprays should be late fall, after leaves fall and in the spring before the leaves come out.

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Maybe there is something unusual about PLC in California. The general recommendation is to use copper and it works 100% in NY. It must be sprayed before bud swell in late winter or early spring depending on location. I’ve never heard that available treatments are not very effective and that is not true in my experience.

The articles I read about this issue were from 2011-2012, so perhaps products have subsequently been developed to improve performance. Here is one of the articles I read:

Getting spray information from the local newspaper is not the best idea. I disagree with the authors statement: “home gardeners now have very limited and less-than-ideal options for treating peach and nectarine trees during the dormant season to prevent leaf curl.” Read some university articles. I’m not aware of any copper spray for PLC that does not work if timing is correct. Lime Sulfur works well but is not necessary.

I also found mention of the issue in a publication on a U. Cal website (but it’s from 2011, so I have no idea whether the information is outdated):

Dormant Treatment MaterialsRecently Discontinued
Two important fungicidestraditionally used to treat peach leafcurlwere withdrawn from themarket in the last year. Lime sulfur(calcium polysulfide) was cancelledfor backyard uses by the U.S. EPA,effective Dec. 31, 2010.Tribasic copper sulfate (sold asMicrocop by Lilly Miller) has beendiscontinued by the manufacturer,although existing supplies can besold and used.As a result, the options for dormanttreatments for preventing peachleaf curl in backyard trees arelimited and less than ideal.Copper ammonium complex is stillavailable but is only 8% copper. Itcan be made more effective byapplying it with 1% oil in the solution.

I also find myself wondering why anybody is using copper at all, given that there are options like @JoeReal’s Italian Dressing, and given that copper is bad for the soil.