As you all know, we who are in Northern California are just about evolving gills and webbed feet from all of these record breaking rainy days we are having. It means that most of our fungicide applications against peach leaf curl will not be 100% effective, and for those who did not apply fungicides against leaf curl during thanksgiving, Christmas time and Super bowl, you will be blessed with curls from the base of the tree to the very tip of your canopy.

This spring time, when we have visible damages to the leaves, it is too late to apply treatment. Ultimately the infected leaves will fall off stressing the tree and weakening it. Removing the infected leaves is a futile effort and will not improve the tree.

But there is something we can do to help out the tree. When it gets warmer and drier later in the season, remove most fruits, apply 50% more nitrogen fertilizer the old cheapo bag of ammonium sulfate to encourage vegetative growth spurt. Also apply epsom salt along with it. This would help alleviate the stress the tree undergoes when losing its leaves to peach leaf curl.

Come fall season, be armed with a full dose of fungicide, and you may need to reapply once again during the bud break.

The fungicide part I have faithfully done but it seemed futile because of all the cool rainy days we are having, the temperature ranges (50-70 deg F) is a paradise condition for the causal fungus, along with slow leaf growth and extended wet record breaking rainy days, there is no fungicide that will work 100% this season. But compared to my neighbors, my trees are still well off.

Like you, my best recourse at the moment is to wait it out, and apply a mixture of ammonium sulfate and magnesium sulfate (epsom salt) by late spring when it is drier and warmer and the peaches starts to extract nutrients from the soil. Fortunately, these fertilizers are so easy to melt in a plastic bucket. I would be using 2 cups (about 1 lb) of ammonium sulfate and 4 oz of epsom salt on a 5 gallon pail of water. Will perhaps apply 15-20 gallons spread around the base of the tree. Apply more if you have a bigger tree, but the dilution above is not harmful to the roots of my trees. This should perk up the tree to develop more greener and bigger leaves.

click the informative links below to learn more:

http://www.canr.msu.edu/vanburen/peacurl.htm
http://www.umass.edu/fruitadvisor/factsheets/leaf_curl_sheet.htm
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7426.html
http://hgic.clemson.edu/factsheets/HGIC2209.htm