Tag Archives: ornamental diseases

Gaura Rust

Gaura lindheimeri is a plant native to southwestern Louisiana and Texas that is becoming increasingly popular as a landscape plant because it is a sun-loving, summer-flowering perennial that once established is fairly drought tolerant. For more on the horticultural merits … Continue reading

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Cercospora Leaf Spot of Hydrangea

Received these photos of Cercospora leaf spot on hydrangea from Gerald Roberts, county agent in Lafayette Parish.  This disease is caused by the fungus Cercospora hydrangeae, which reproduces on infected leaves that have fallen to the ground. The spores produced … Continue reading

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Powdery Mildew Blighting Crape Myrtles Now

Powdery mildew, caused by the fungus Erysiphe lagerstroemeriae, is once again wreaking havoc on the blooms of susceptible crape myrtle varieties. The warm, humid weather during late spring and early summer has been ideal for disease development on plants in partially … Continue reading

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Impatiens Downy Mildew Update

Downy mildew was observed on Impatiens walleriana in a residential landscape in New Orleans today. The affected plants had been purchased at a “big box” store in the area, but it was not the same chain as the store in the … Continue reading

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Impatiens Downy Mildew Makes Its First Confirmed Appearance in the Louisiana Landscape

We had our first confirmed report of downy mildew on Impatiens walleriana here is south Louisiana this weekend. My wife commented that one of the double impatiens that she’d gotten at one of the big box stores a couple of weeks … Continue reading

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New Oomycete-specific Fungicide from Syngenta

Micora™, a new fungicide from Syngenta, is now registered for use on greenhouse and outdoor ornamentals and vegetable transplants to be sold to retail consumers. Micora™ contains the active ingredient mandipropamid (a carboxylic acid amide), which is specific for the … Continue reading

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Rose Downy Mildew Is Active in Louisiana

Received a call from a local garden center last week regarding downy mildew on a shipment of roses from California that they had hoped to sell for Mother’s Day. Symptoms on the somewhat resistant cultivar Mr. Lincoln could easily be mistaken for … Continue reading

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