NOURISH No. 4 – Managing
Leaf curl
Dave Askin, 30/4/2015.
Summary
Worth spraying! Autumn / winter leaf fall, and spring bud burst. If lots of rain in spring, well, spray
again. Use winter oil in the autumn to help make the spray stick.
Use a spray with lots of Copper. Refer below.
Detail notes - Leaf curl in peaches and nectarines
From http://www.oderings.co.nz/leaf-curl-__I.53980__N.55031
Leaf curl is a fungal disease mainly
affecting peaches, nectarines, and other
stone fruit in spring. Unfortunately by the
time we notice it in spring, it’s too late to fix
the problem. Still, I would recommend
picking up any fallen leaves and to use the
‘miracle’ products that you will read about
below. As with all good gardening practices,
prevention is key. Leaf curl winters over on
the plant, so to eradicate the disease you
must spray at three critical times.
1. When the plant is dormant during winter (i.e., it has no leaves), spray it with Lime
Sulphur, Liquid Copper, or Champion Copper. (Note: Don't use Lime Sulphur on apricot,
pear or apple trees as it is said to cause russet.)
2. Just before bud burst (i.e., when you see green swellings along the branches), spray with
Champion Copper or Liquid Copper.
3. After the petals fall, leaving tiny fruit behind, spray a third time, again using Liquid Copper
or Champion Copper.
A few years back I had given up hope on two unusual but delicious fruiting trees, one being a
nectarine and the other a peach. I am meticulous about spraying at the appropriate times, but still
these two trees were affected with this disease year after year, which I found disheartening. I
was speaking to a work collogue a few years back, saying that I was considering ripping out
these trees, and she recommended using Magic Mulch.
Magic Mulch is a combination of nature’s two most beneficial growth aids: sphagnum moss and
seaweed. I incorporated Magic Mulch into the soil around my two problem plants, and they have
thrived. (Yes, like a miracle, they have had no leaf curl for three years running.)
I go a step further and add either Ocean Solids or Ocean Organics every three months to feed
the trees and to stop the leaf curl. Both of these products provide nutrients and minerals from the
sea. These three products, along with my Neem Granules, help me maintain my garden, keeping
our 30 fruit trees and our huge vegetable patch insect and pest free.
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If you have a problem with leaf curl or just want to have healthier plants and fewer insect
problems, use any or all of these three products this year, and if you have any comments or
questions email us at info@oderings.co.nz.
3 Comments
#3anagenna31/08/201421:22Nasturtiums under the peach trees seem to have an effect too!
#2Debbie10/08/201412:30We had trouble with leaf curl on our peach tree in Timaru for years and as we
prefer not to spray, discovered that growing runner beans up the tree completely eradicated the leaf curl!
Definitely worth a try.
And from http://www.gardeningknowhow.com/edible/fruits/peach/peach-leaf-curl.htm
Controlling peach leaf curl with fungicides is the only way to prevent this
disease. So what are the most effective fungicides for peach leaf curl? The
safest and most effective fungicides available to home gardeners are fixed
copper products. These may be listed as ‘metallic copper equivalent’ or MCE
on product labels. The higher the MCE, the more effective the fungicide will
be. Other, less effective, fungicides include lime sulfur and copper sulfate.
And from Yates http://www.yates.co.nz/problem-solver/problems/peach-leafcurl/
Leaf Curl is a fungal disease which overwinters in the crevices of the tree bark and around the buds. One or two
well timed applications for most stone fruits should control the disease. The timing of the fungicide spray varies
with differing stone fruit varieties. For apricots, spraying at 90% leaf fall and again as buds show pink is
recommended. For peaches, spraying is best in late winter when buds first swell (bud scales start to loosen).
Yates Bravo, Yates Copper oxychloride, Natures Way fungus spray.
From - http://www.ipm.ucdavis.edu/PMG/r602100311.html

consider using a sticker or winter oil as an adjuvant to increase persistence, and

plan to make two applications. At least!
And for the keen folk This gets a tad complicatedhttp://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7426.html
Fungicides
Copper
Historically, the most commonly used fungicides available to home gardeners have been the fixed
copper products. For all copper-containing products, the active ingredient, copper, is listed as
“metallic copper equivalent,” or MCE, on the label. Various product formulations differ widely in
their metallic copper content. The higher the MCE, the greater the amount of copper and the more
effective the product will be. However, other factors such as coverage, use of additives as such
stickers and spreaders, and frequency and duration of rain, which can wash off the copper, also
will impact product effectiveness. In all cases, the copper is active only when it is wet, when the
copper ions are in solution.
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Fixed copper products include tribasic or basic copper sulfate, cupric hydroxide, and copper
oxychloride sulfate (C-O-C-S), but currently only liquid products containing copper ammonium
complex products with 8% MCE (e.g., Kop R Spray Concentrate [Lilly Miller brands] and Liqui-Cop
[Monterey Lawn and Garden]) are available to consumers. The most effective copper product, 90%
tribasic copper sulfate with a 50% MCE (Microcop), is no longer available to retail outlets, because
the manufacturer withdrew the product in 2010, although remaining supplies still can be sold.
The copper ammonium complex products can be made more effective by adding 1% horticultural
spray oil to the application mix; the oil also aids in controlling some aphids, scale insects, and
mites. Copper soap (copper octanoate) fungicides are also available, and preliminary research
indicates they may provide some protection of trees.
Be aware that repeated annual use of copper products over many seasons can result in a buildup
of copper in the soil, which eventually can become toxic to soil organisms, and if it moves into
waterways, can harm some aquatic species.
Bordeaux Mixture
Copper sulfate is not a fixed copper and, when used alone, is less effective than tribasic copper
sulfate or other fixed copper products. However, if copper sulfate is mixed with hydrated lime to
make a Bordeaux mixture, the copper sulfate and calcium in the lime react together to form a
fixed copper product that is effective against peach leaf curl. Bordeaux mixture is not available for
sale; it must be mixed up just before application, and the ingredients can be very difficult to find.
For information on preparing Bordeaux mixture see Pest Notes: Bordeaux Mixture.
Other Fungicides
The synthetic fungicide chlorothalonil currently is the only other noncopper fungicide available for
managing peach leaf curl on backyard trees. Lime sulfur (calcium polysulfide) products no longer
are registered for backyard use.
Application
Thorough coverage with any fungicide is essential to obtain adequate disease control. Trees should
be sprayed to the point of runoff or until they are dripping. When using pesticides, always read
and follow the label for usage, rates, toxicity, and proper disposal. Proper protective clothing and
gear including goggles should be used when handling any pesticides.
Physical Controls
Although symptoms of leaf curl are seen primarily in spring as new leaves develop, there is little
you can do to control the disease at this time. Some people remove diseased leaves or prune
infected shoots, but this has not been shown to improve control. Normally, diseased leaves fall off
within a few weeks and are replaced by new, healthy leaves, unless it is rainy. If a tree is severely
affected with peach leaf curl this can stunt its growth, so consider thinning fruit later in the
season. Pruning in fall prior to applying any fungicides can reduce spore numbers overwintering on
the tree and reduce the amount of fungicide needed. If leaf curl symptoms occurred on your trees
in spring, be sure to treat the following fall and/or winter to prevent more serious losses the
following year.
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