Home > Great Big Greenhouse Blog > June 2015 > GARDEN TALK with DOUG - PLANT LOVERS - WE HAVE A PROBLEM - FUNGUS PROBLEM THAT IS!!


I am interrupting my monthly blogs on perennials in order to highlight a problem that we are having with our dogwood trees and our turf.  Over the past week I have had numerous customers bring in pictures or samples of problems that they are experiencing with their dogwood trees and their grass. 
DOGWOOD TREES - The problem with the dogwood trees is due to powdery mildew.  This fungus attack is causing our dogwood trees to defoliate and drop their leaves.  It is especially noticeable now that we have turned hot and humid after experiencing a rather cool and wet April.  The symptom is patches of white powdery fungal growth on the upper surface of newly emerging leaves.  This infection will cause the new growth to be twisted or deformed.  Older infected leaves have brown or purple blotches on the leaves. 
                I talked to our Chesterfield County Extension agent, Mike Likins, for his input and advice.  Treatment is recommended.  Anything that can be done to preserve and promote refoliation is encouraged.  Fertilizing is NOT recommended.  These fungi are after nitrogen primarily so any additions should be based on soil testing.  Mr. Likins recommends the product, Propiconazole.  Propiconazole is found in a very popular fungicide by Bonide called INFUSE.  Infuse is a systemic disease control product.  It is thought that are dogwood trees will survive this attack of powdery mildew with some TLC.
LAWNS  -  Most of us have tall Fescue lawns.  Unfortunately, tall fescue has one major weakness, and that is its susceptibility to brown patch fungus.  As the name implies, brown patch appears as roughly circular patches that are brown, tan, or yellow in color.  The months of June, July, and August tend to be the peak periods for brown patch activity in Virginia.  Warm nights combined with long periods of leaf wetness from afternoon thunderstorms, irrigation are ideal conditions for brown patch development.  Nitrogen fertilizer, irrigation, and mowing are the contributing factors to developing brown patch.  For best results, tall fescue should be mown at heights between 2.5 and 3.5 inches.  Irrigation plays a role in developing brown patch fungus.  Irrigation should not be used just before sunset or just after sunrise.  Instead, irrigation should be done between midnight and 6 AM.  Lastly tall fescue should not be fertilized with nitrogen in late spring.  Nitrogen encourages tall fescue to produce soft leaf tissue that is easily infected by the brown patch pathogen.
                A turf fungicide is needed once brown patch develops.  There are many good fungicides on the market for control.  Bonide’s  INFUSE is one excellent example of a systemic lawn fungicides for controlling brown patch.
Next week I will continue my blog on highlighting a shade loving perennial to celebrate June as Perennial Garden Month.
Posted: 6/18/2015 by Doug Hensel | with 0 comment(s)
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