Fruit diseases are becoming active

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By Dennis Morgeson

Fruit crop diseases are starting to appear!  With all of the wet weather lately, I am actually surprised that it hasn’t gotten worse than it already is.  Apples are showing signs of frogeye and apple scab.  These area early diseases of apples and relatives such as crabapple. If you have frogeye the leaves will have a small brown spot with a lighter tan colored interior. Apple scab will have darker less symmetrical lesions without a lighter tan interior.
In both cases the spots become numerous and the leaves turn yellow and fall off.  Both of these diseases can be well controlled with applications of maneb, captan, moncozeb, or daconil but with the wet weather the fungicide has been washed off repeatedly.
Peach leaf curl is showing up on peaches where the leaves become puckered and can turn purplish, in extreme cases most leaves on a particular tree can become infected.  If you see peach leaf curl now there is nothing you can do now.  The control time for peach leaf curl is during dormancy in December or January with a single spray of liquid lime sulfur.
Raspberries and blackberries including wild varieties have become infected with orange rust.  This disease is easily recognized by the covering of moldy looking orange rust on the leaves.  If you have a plant or plants infected with orange rust they should be removed root and all and destroyed.  You must also discard wild plants as well that are showing orange rust diseases symptoms.  There is no control of orange rust however you can plant resistant varieties and discard any plants that may be infected.
Anthracnose is becoming active on grapes with the signs being numerous small circular lesions on leaves, stems, and developing fruit.  The lesions will be reddish brown raised or sunken areas.  Once anthracnose is established in a vineyard it is hard to control.  There are systemic controls on the market for commercial growers however homeowners can use protectant fungicides like daconil, captan, mancozeb, and maneb.
It is important that we become diligent about applying fungicides between rains.  The prolonged periods of wet weather combined with the temperature variations conditions are ripe for fungus development.  In the next few weeks I suspect the tomato diseases will become active as well as more and more gardeners get their vegetable gardens planted.
The Washington County Garden Club will meet at Mama’s Touch Nursery in Fredericktown this Thursday, May 19, at 6 p.m. The Wheelbarrow Class on growing pumpkins and sweet potatoes is scheduled for May 26 at the Washington County Extension Office at 6 p.m. There are still slots available with the cost being $10 and you will take home numerous sweet potato sets and varieties of pumpkins to try as well.
Happy gardening!