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Dallas Morning News - July 6, 2017


Black spot on roses.

Plant diseases are easy to control – easy, that is, if organic techniques are being used. The key is balance. The key to balance is a healthy population of microorganisms. Diseases are simply an imbalance of microorganisms in the soil and in plants. Organic gardeners have relatively few disease problems because the organic soil building techniques and products help keep microbes in healthy populations. 
When problems do pop up, disease control in an organic program is simple and effective. All organic products help control diseases to some degree because they stimulate microbes. When soil and plants are healthy, there is a never-ending microscopic battle being waged between the good and bad microbes, and the good guys win. Disease problems are simply situations where the microorganisms have gotten out of balance.

Powdery mildew on crape myrtle.

Drainage is a key ingredient for the prevention of diseases. Beds or tree pits that hold water and don’t drain properly are the ideal breeding places for many disease organisms. Too much water and plants too deep in the ground are leading causes of disease issues. As with insect pests, spraying diseases only treats symptoms, not the real problems. The primary cause of problems is usually related to the soil and roots making it critical to improve drainage, increase air circulation, add quality organic products to stimulate and protect the living organisms in the soil.

Gray leaf spot on St. Augustine.

Plant diseases include fungi, bacteria and viruses. Fungal diseases are the most common. They include powdery mildew, early blight, brown patch, black spot, grey leaf spot, etc. These diseases can be knocked back with several different organic sprays such as milk at 1 cup per gallon of water, hydrogen peroxide at a 1-2% solution with water, baking soda or potassium bicarbonate at a rounded tablespoon per gallon of water and with commercial products such as BioWash and BioSafe. Bacterial diseases such as fireblight can be successfully treated with hydrogen peroxide or commercial products containing hydrogen peroxide. Viral diseases such as mosaic virus, curly top and rose rosette can be managed with the hydrogen peroxide products. Several soil diseases can be overcome with whole ground cornmeal because it stimulates a beneficial fungus called trichoderma. 

Brown patch on St. Augustine.

Of course, all these techniques only work when a non-toxic organic program is being used. Toxic chemical disease control products don’t work because they are indiscriminant. They kill the beneficial microbes as well as the targeted pathogens. Then the pathogens grow back faster than the beneficials. So - go organic and enjoy your healthy gardens.

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