By Island County Extension Agent, Donald B. Meehan
PEACH TREES STRUGGLE IN WESTERN WASHINGTON
This is an important time of the year for the many Island County residents trying to grow peaches. Often this particular tree fruit endeavor is a challenging experience. The reason for this struggle is the peach tree's susceptibility to the disease Peach Leaf Curl.
Now is the time of the year to begin controlling the disease. Chances are that you have all seen the symptoms of this disease on yours or your neighbors peach trees. Normally the symptoms are seen on the foliage as curly, crinkled, thickened, and discolored leaves. As the leaves develop in the spring they will often appear yellow to reddish. They will be thick and crispy in texture. Normal leaves are generally soft and pliable. A white or gray coating of spores appear on them as the infected leaves develop. Curling and crinkling has pretty well set in by mid season, and if the season is a damp one these infected leaves will stay on the tree turning first yellow and then brown. At this stage is common to see them remain on the tree after all others have fallen off.
The fruit, if any is developed, will often exhibit irregular, swollen red growths on the surface. These areas usually lack the normal peach fuzz. Sometimes the twigs are distorted as well.
Defoliation occurs throughout the growing season. New leaves which are formed can appear normal and uninfected. The damage that the tree sustains is in terms of stress from defoliation. Uncontrolled, the tree will be so stressed that it will finally die.
Peach Leaf Curl is caused by a fungus Taphrina deformans. The spores of this fungus are produced on the surface of infected leaves and are washed or blown into bud scales in late winter as the buds begin to swell. The spread of these spores can be controlled if action is taken in the form of good tree sanitation and a fungicide spray program.
Good sanitation involves removing all diseased leaves whether they are hanging on the tree or falling at the base. Diseased leaves need to be burned or put in the trash. Preventing reinfection requires applying a protective fungicide at least twice during the winter. The first spray should be put on in mid December and the second, most important one, in late January or early February, just as the buds begin to swell. You have to be a bit of a detective to learn when the buds are swelling. Get out there now to look at your buds, note their size and shape. Make notes, if necessary, so that when January comes around you will be able to notice bud swell changes.
There are several fungicides available which will control Peach Leaf Curl fungus. The one which recent research is showing the most promise in terms of effectiveness, is called Cyprex. This fungicide is a bit difficult to find and isn't generally sold in homeowner-size packages. Lime sulfur, Ziram and Bordeaux are commonly available fungicides. Be sure to follow label instructions for mixing with any of these chemicals.
Should you miss spraying at the times I pointed out you can keep your sprayer in the garage for another year. Spraying just won't work after buds have started to open. Fungicides act as a protective barrier, they do not kill a growing fungus which has invaded plant tissue, they only prevent infection from occurring.
If you have peach, nectarine or almond trees the WSU-Cooperative Extension publication called "Peach Leaf Curl" will provide most of the answers in controlling this disease. Also available is a publication called "Disease & Insect Spray Schedule for Home Orchards: Peaches, Apricots, Plums & Cherries". Both can be obtained by contacting our office.
Return to Articles Index
Return to Garden Page
Providing Educational Support to the Island County Community