Podosphaera leucotricha . . . it’s a mouthful to say, and it’s a handful for apple growers, as it’s the fungus that causes Powdery mildew. One of a group of diseases that threaten healthy orchards, Powdery mildew can cause trees to lose vigor, and yields may be affected. The good news is that orchards can be protected, and spring is a key time to take proactive steps in that process.
What It Looks Like
Powdery mildew grows as a white mass on new terminal growth of apple trees that will eventually envelop shoot tips. As the disease progresses, secondary infections can occur on leaves, blossoms and fruit. Leaves typically display the gray-white powdery growth, usually on the undersides. And fungal fruiting bodies may be seen by midsummer, when Powdery mildew fungal mats turn brown.
Apples become most susceptible during the period around petal fall, and affected fruits typically show a brown, corky, net-like condition (known as russeting) in infected areas. When fruit are infected, the surface may become discolored and sometimes dwarfed.
To make things even more challenging, Powdery mildew is unique in that it can infect apple trees in the absence of rain or dew. Even without moisture, apples may be susceptible to disease and should be protected.
Early treatment is important in addressing Powdery mildew to stop the disease in its tracks before it can cause secondary infections. It also helps maintain photosynthetic efficiency within the trees, which keeps foliage from becoming brittle or curled and distorted in appearance.
According to Washington State University, disease control is warranted if trees are still actively growing. To help stop the threat of Powdery mildew in orchards, growers rely on the protection in PROCURE® Fungicide from Arysta LifeScience. A locally systemic broad-spectrum fungicide, PROCURE gives growers peace of mind as well as long residual control through season’s end to control Powdery mildew and its threat for the future growing season.
PROCURE is rapidly absorbed by the apple tree and performs well on secondary fungi such as Scab and Cedar apple rust. Applications should be made at the first sign of mildew, usually at the ½” green tip stage, and should continue at 7- and 14-day intervals as needed through the terminal growth period.
PROCURE also makes a strong tank-mix partner as part of a comprehensive crop protection package. Some apple growers partner it with PH-D® Fungicide – PH-D provides extra power to knock out Powdery mildew while PROCURE gives apple growers long residual control of the disease. KASUMIN® Bactericide, which also can be tank-mixed with PROCURE, protects apples against Fire blight without any resistance or cross-resistance issues.
To learn more about Powdery mildew control for apples, visit http://www.arystaspecialty.com/pomefruit or contact your local Arysta LifeScience sales representative.
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The Fight Against Fire Blight
No one knows more about the fight against Fire blight, caused by the bacterium Erwinia amylovora, than Dr. George Sundin, professor in the Department of Plant, Soil and Microbial Sciences at Michigan State University. Through his ongoing research and work with the U.S. Department of Agriculture, positive strides have been made in crop protection products that help control this devastating disease.
State registrations may be pending. Always read and follow label directions. PH-D is a registered trademark of Arysta LifeScience North America, LLC. PROCURE is a registered trademark of MacDermid Agricultural Solutions Inc. KASUMIN is a registered trademark of Hokko Chemical Industry Co., Ltd. Arysta LifeScience and the Arysta LifeScience logo are registered trademarks of Arysta LifeScience Corporation. ©2017 Arysta LifeScience North America, LLC. SPC-1733