Friday, August 31, 2012

Some Impatiens Severely Impacted By Disease



Previously, Impatiens have been a virtually bullet-proof selection for summer seasonal color. One of the best choices for shady locations, Impatients are even good in sunny locations with good irrigation. However, a new threat has come on the scene called Downey Mildew. This pathogen, known for many years in other parts of the U.S., has become an exceptionally damaging pest here just this season. The disease has the potential for widespread and rapid destruction of Impatiens. Luckily, Impatiens are the only plant we have seen affected.

We started seeing a few plantings show signs of Downey Mildew in late July. We worked with out grower and chemical supplier to develop a management strategy. We have treated all of our Impatients twice so far with two different fungicides and plan to treat them twice more. These fungicide treatments are outside of our standard program and will be billed as an extra but we are working to keep the cost as low as possible. Our treatment and cost will be discussed with impacted clients individually.

Unfortunately, this disease is difficult to control and the earliest affected plantings were too far gone for our treatments to be effective. We hope that our control plan will be successful with those plantings not yet affected. We have learned that the diesease is not curable, but hopefully preventable. Once affected, most plantings will fail. So far, we have only had a small percentage of our plantings infected and our control program appears to be protecting most plantings.

What's next? Hopefully our current treatment plan will protect most plantings through the remainder of the season. For those plantings lost, we recommend planting pansies early and will discuss this option with those affected. As for the future, we are in discussion with our grower and may move away from Impatiens until this disease is better understood and more easily controllable. We will keep you informed.

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