Search the Archives


peach leaf curl treatment, your approach

peach leaf curl treatment, your approach

I did a typical copper dormant spray this past year. Actually I did it three times: once in the fall with 90% of the leaves dropped, once around January and once when the buds began to swell. My heavenly white nectarine is still covered in leaf curl. Interestingly my miniature necta zee has almost none, showing there are major differences in natural leaf curl immunity.

Anyway, for next year I want to know the best technique for leaf curl prevention. What has worked best for you and precisely when do you treat. Thanks.


The following thread was started by Brett Elicker on May 16, 2010 at 6:10 pm PST

We just has a discussion, not too far below

We just has a discussion on peach leaf curl, but not sure anything was really decided, which was best.
I used the optional link below, but just in case it does not work, here is the URL address. We all seem to have our own answers, even if our methods are not all fully effective under different situations.


The above followup was added by David Johnson, Waterford CA zone 14 on May 16, 2010 at 6:44 pm PST.

saw that

Yes, I read that one with great interest, however it seemed to focus on non-dormant sprays such as serenade. I was hoping for a discussion of comprehensive care including dormant spray and timing. Thanks.


The above followup was added by Brett Elicker on May 16, 2010 at 6:47 pm PST.

Brett, Tea Tree oil.

I don't like the harsher chemical sprays, so did some research and tried many natural solutions, but none were very effective. One day I thought, I use Tea Tree oil on my body for infections, bacterial and fungal, so why not on a plant, after all it came from a plant in the first place.

I started with adding 1/4 ounce of fine grade tea tree oil to 1 gallon of premixed Volks dormant oil spray, before pink bud. I had slight breakouts on some more sensitive nectarines, so up the mix to 1/2 once of tea tree soil to 1 gallon of premixed Volks or etc dormant oil spray.

The most I see are a few pea size red bubbles on a tree, not more. This year as I explained, I sprayed and it rained a few yours later. But could tell most stayed, but did have a slight flare up on the neighbors peach tree, but it was only one weeks leaf set, none before and now later, that was a bit strange.

I know it works great for me here in Waterford CA, but cannot be sure how it would work in Bay Area and it greater humidity.

Cosmetic/heath food grade Tea Tree oil is not cheap, runs around almost $10 per ounce, but for a one time application, no worry later lone and natural, I love it.

I would assume if one could make the right connections, a less expensive form could be had. I am able to spray my 5 stone fruit trees, my pomegranate tree, some young figs, quince and etc and my neighbors young peach, cherry and apricot tree with two gallon of mix.


The above followup was added by David Johnson, Waterford CA zone 14 on May 16, 2010 at 7:11 pm PST.

my solution for peach curl

B...we had an unusually damp Spring in SoCal this year. In the past...I have had leaf curl issues. I sprayed twice this winter with lime/sulphur with great success. A couple of keys which I noticed: 1. spray when there will be several days of dry weather following 2. spray all limbs to the point of run-off. I think somebody has mentioned that it is tough to find lime/sulphur now. I don't know.

The above followup was added by Ed of Somis on May 16, 2010 at 7:20 pm PST.

Figured it out!

I did a little research, and found a few interesting tidbits. Understanding the lifecycle explains exactly how to treat peach curl.

When there is peach curl during the growing season, ascospores are released into the air, carried to new tissues, and bud (divide) to form bud-conidia, which are asexual spores. Note that these do not cause new peach curl infections at that time, they will cause infection the following year. This is because the only way peach curl can infect tissue is if the spores get washed into the buds during Winter rains.

The fungus survives the hot, dry summer as ascospores and bud-conidia on the tree’s surfaces. When the weather turns cool and wet in fall, the ascospores germinate to produce more bud-conidia. The new and old bud-conidia continue to increase in number by budding. Eventually a film of bud-conidia is formed on the tree’s surface.

Infection occurs when the bud-conidia are moved inside the swelling buds by splashing water from irrigation or rain.

So there are two specific times to intervene: once in the fall, immediately after leaf fall, and once in the Spring, when buds begin to swell. In the Spring spraying, it's important to make sure each bud gets saturated with fungicide. Apparently, many of the modern fungicides are not very effective, lime-sulfur seems to still be the most effective agent.

My experience is that a mid-Winter spray is not very effective. By then, if there has been a lot of rain, the spores are already growing everywhere. One really has to spray right after leaf Fall, preferably before the first rains, and then once again in the Spring.

Spraying once the infection is there is useless. The best solution is to feed the trees a lot of nitrogen to stimulate new leaf growth. But I still pluck and discard all the infected leaves to prevent them from sporing and spreading the infection.

I don't know if it's really accurate that the fungus can't infect emerged leaves. But that is what University of Michigan extension claims and seems to make sense. My late Spring sprays have been totally ineffective. Basically, either peach curl is already inside the leaf in the bud, or it's not. Spraying infected leaves has no effect.

The above followup was added by Axel on May 17, 2010 at 8:18 am PST.

Thanks Axel, that was enlightening

Thanks Axel, that was enlightening, I had never thought about researching how it operated. So it could help to spray before

One thing about Tea Tree oil and other essential oils, they are very fine and penetrate very easily, even on ones own skin. I think it penetrates easily into the buds, buds but also into the tender twig grow, and actually might be going systemic. I have chatted with a few who also wonder if this is not the case, but we have no proof; Neem oil seems to be in the same boat.

I spray just before pink bud, knowing it is the best time to also catch other awakening bugs, eggs and diseases. Always figured winter was not a good time to spray, being raised on a farm and with almonds when I was growing up.


The above followup was added by David Johnson, Waterford CA zone 14 on May 17, 2010 at 11:28 am PST.

Neem oil and apple rust

Not sure how this might tie in but just tried AZ41 on apple rust. It has tea tree oil as one main ingredient. It seemed to work almost immediately. Not certain what I am seeing but it looks like all the areas which were rusted have become necrotic spots and the rust is gone. I will know more in a few days.
In San Diego we are entering the time of year when we have high humidity every day. Night and morning low clouds with some afternoon clearing. Often no afternoon clearing. So it is important to keep after fungal infections. No irrigation on the leaves, water in the early mornings and make sure there is air flow through the plants.

The above followup was added by George on May 17, 2010 at 11:44 am PST.

varietal selection

Living almost right on the beach, I have little choice but to grow PLC-resistant cultivars exclusively. As a result, I don't do anything to my peaches. In the past, some literature has stated that some flavor genes might be linked to PLC susceptibility and genetically-resistant strains are inherently less flavorful. Not being in a very good peach-growing climate to begin with, I would have to say that two PLC-resistant cultivars, 'Frost' and 'Q-1-8', a white peach, are surprisingly good even so...probably as good as any peach could be in this kind of climate. They're not the equal of an 'Arctic Supreme' or 'Rio Oso Gem' grown in Sacramento, but they're pretty good for the coast!
Particularly if you freeze, can or make smoothies with many of your peaches, PLC-susceptible strains just aren't worth it unless you live far enough inland that it is a minor issue.

The above followup was added by Steve in Brookings on May 17, 2010 at 4:43 pm PST.

My frost peach is the best yellow peach I have

Steve, frost is delicious and rivals any of my other peaches. The literature is bogus, don't believe it. My frost peach this year is loaded, I am a little concerned about how cool it's been, but hopefully we will get some more heat soon. It feels like the middle of Winter right now.

The above followup was added by Axel on May 17, 2010 at 8:06 pm PST.

Please note that you are viewing posts from the vintage Cloudforest forum. These are un-moderated posts made by un-registered users. Every effort has been made to clean up the old archives, but we cannot guarantee the contents. If you find an offensive post, please bring it to our attention and we will remove it.

It is not possible to post to the old archives. If you wish to follow up on one of the posts in the archives, please make a reference of the post URL and start a new topic in the Fruits, Rare Fruits and Exotics forum.


Welcome Guest

Please register or login if you would like to post. It is currently Fri Nov 24, 2017 3:48 am. (All times are UTC - 8 hours [ DST ]).

Getting Around the Cafe


Who is online

In total there are 447 users online :: 8 registered, 0 hidden and 439 guests (based on users active over the past 300 minutes)
Most users ever online was 977 on Fri Feb 24, 2017 8:19 pm

Registered users: Bing [Bot], Facebook, Google [Bot], Google Feedfetcher, Magpie [crawler], Majestic-12 [Bot], Twitter, Yahoo [Bot]