Peach Leaf Curl

(Taphrina deformans)

 

Big Picture:

To prevent the damaging effects of peach leaf curl, you need to spray the branches or your tree before the buds open up. For many, this means spraying in the early spring.  However, in Southern California it is often in mid winter.

 

What is it?

Peach Leaf Curl is caused by a fungus that damages and deforms leaves.  The fungus is known by the name Taphrina deformans.  If severe, the infection can reduce crops and stunt trees growth.

 

How do you get it?

The fungal spores are everywhere, (in the air and soil) so they cant be avoided.  In the winter the fungal spores can be seen with a microscope if you look at peach tree branches and fallen leaves.

 

What can you do about it?

You need to do two major things to help your peaches and nectarines fight this scourge.

1. Remove all of the dead leaves around your tree(s) because they are coated with the fungus.
2. Spray with antifungal spray in the dormant season.

• ***The most important element for success is to spray the buds in the dormant season***  Spraying after bud break doesn’t reverse the damage.

My specific method to fight Peach Leaf Curl:

• I am using a mix of “Bonide All Seasons oil”  and Bonide Copper Fungicide.
• I just use the recommended concentrations of both in the same spray bottle.
• For best results, spray the buds in January and again just before bud break in the late winter/early spring.

Additional info:

• The oil helps the fungicide to stick to the branches and will also help to kill over-wintering insects and their eggs such as  scale, mealy bugs, whiteflies, etc.
• Note of caution; repeated use of copper spray can build up in the soil over years and can become toxic to soil organisms.  Therefore, be careful to only use enough to cover the branches and not soak the soil.
• Additional side note: I recommend that you get (and label) a separate garden sprayer for each of your different garden needs.  That way you don’t have to worry about spraying residue of something like an herbicide on a plant that you would actually like to keep around.  It is also nice to have a garden sprayer with an angled spray nozzle so you can easily get the bottoms of the leaves.

What else can you do about it?

In some wetter parts of the country, many people have reported success with strategic planting positioning to combat peach leaf curl.

• The main idea is planting in a location that promotes dry leaves which makes them less susceptible to fungal infection.
• One idea is to plant your tree under a protected eve to keep them dryer from rains.
• On the same note,  training your tree as an espalier along a south facing wall may also  help to keep leaves dry.  However, at least in Southern California, planting along a south facing wall may be a location that becomes too intense in the hottest summer months.  Aggressive watering in the hottest parts of the year may help to overcome the problems of extra reflected light and heat from an adjacent south facing wall.

 

When do you spray?

• In an ideal world, you spray in the dormant season after the leaves have fallen and before bud break.  You also don’t want to spray when the rains will just wash it away before bud break.  Timing can be a challenge.
• If you don’t spray before new leaves emerge, you missed the window and the leaves will be infected.  At this point it really doesn’t matter how much you spray, it won’t do anything.

 

Southern California timing:

• In Southern California, spray timing can be very tricky.
• Many peaches down here in SoCal won’t lose their leaves until January and sometimes they don’t lose all of their leaves before new leaves emerge.
• I have noticed that this is a particular challenge with Florida Prince Peach trees.  For example, in early January, my Florida Prince Peach trees will still have some leaves, and at the same time at the same time that buds swelling – ready to open.

For additional information; UC Davis goes a bit deeper into the disease.