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What is the likely cause of the bobbly forms on the leaves of a peach tree? Does it matter or is it just some natural anomaly that doesn't affect the tree's health? If is it a concern how can it be treated?

The tree in question is about 1m (3 ft) tall, so not very close to maturity yet.

On the left is a bottom view of a bobbly leaf; on the right is top view.

UPDATE: Further to the question, can anyone give information about how leaf curl is different when cause by a virus (e.g. Begomovirus) instead of the Taphrina deformans fungus which is apparently the much more common cause? And how would treat it differently?

Peach leaves showing bobbly forms enter image description here

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  • 1
    To clarify, are the leaves crinkly (ie. curved), or do they have growths on them (like galls)?
    – winwaed
    Dec 18, 2011 at 16:10
  • 1
    @winwaed The first one - crinkly without any specific growth visible to the naked eye.
    – Lisa
    Dec 18, 2011 at 23:00

2 Answers 2

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Pretty sure that's Peach Leaf Curl. My tree's were hit by that pretty bad this last year. I spoke with a few people and from what I understand the solution is to apply a fungicide in either late fall (when most of the leaves are gone) or early spring (when they are budding). Something like this

I sprayed my tree's down but I haven't had a chance to see how well it works. Hope this helps!

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  • Thanks Abe. The advice applies to eastern US. Do you know if this would apply in South Australia, south coast?
    – Lisa
    Dec 18, 2011 at 23:09
  • According to Wikipedia it is. en.wikipedia.org/wiki/Leaf_curl I know that it's fairly common over here on the west cost of the US, so it's definitely not limited to the Eastern US Dec 18, 2011 at 23:50
  • Do you know of a copper-based soap spray that would be useful as a fungicide (though won't be needing it until May)? Either brand names, links or info on how to make it yourself would be very helpful. Also bear in mind that I might not be able to access American brands.
    – Lisa
    Dec 19, 2011 at 0:54
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    Unfortunately I don't. My wife bought the spray we used, so I didn't see the label. Even if I had, I'm not sure if it's US specific or international. We just went to our local nursery and when we told them what we wanted they knew exactly what we were talking about. Dec 19, 2011 at 2:45
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I agree with @Abe Miessler's diagnosis of peach leaf curl. Last year one of my peach trees had a bad case of this -- the other one 30' away was mostly unaffected. (One of the recommendations for prevention is to plant resistant varieties.)

I'm not sure where I read this, but once you've got it, you can't cure it this season -- you can only prevent it next season.

The Organic Gardener's Handbook of Natural Pest and Disease Control (Bradley et al) describes peach leaf curl on p. 324:

  • Plant resistant cultivars.
  • Remove and destroy infected leaves.

That reference says it's worst in cold, wet springs. You can apply a preventive spray of lime sulfur (calcium polysulfide) (or "Bordeaux Mixture" -- a copper spray) either in the fall after leaf drop or in the spring before bud break. (See The Backyard Orchardist (Otto), p197.) Beware that copper-based sprays are toxic to fish and earthworms (at least), so don't overdo it. Beware that sulfur sprays can be toxic to the plants in hot, dry weather (see links below). Either of these sprays are fairly generic items that should be available at a well-stocked garden center or nursery.

It may not be practical advice for you at this point, but Handbook also suggests growing dwarf trees in pots where they won't be cold and wet in spring and then moving the pots outside for the summer.

Some other info:

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  • The idea of growing in a pot is a good one but in this case, it's already fairly established in the ground so I wouldn't dig it up. As to growing resistant varieties, I heard a rumour that the fruit is inferior so I'm not sure it's a tradeoff I'd make.
    – Lisa
    Dec 20, 2011 at 2:13
  • I've added an addendum to the question to try and get a more complete answer. Can you help?
    – Lisa
    Dec 20, 2011 at 2:20
  • @Lisa: I'd prefer inferior fruit to none at all, but I have fewer varieties to choose from to begin with (cold winters). Sorry that I can't help with the extra question. I think the lime sulfur spray kills the spores from the fungus. I don't recall reading anything about virucidal properties.
    – bstpierre
    Dec 20, 2011 at 2:42

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