To bring disease-resistant Impatiens back to gardens everywhere, it took a dedicated team and collaboration of plant breeders and researchers at PanAmerican Seed. Through their hard work, the next generation of Impatiens walleriana is ready to take the stage.

What is Impatiens Downy Mildew?

Since 2011, Impatiens downy mildew (IDM) has decimated Impatiens beds across the globe. IDM is caused by a host-specific water mold, Plasmopara obducens. When present, and environmental conditions are met (high humidity and cool night temperatures), the disease can spread rapidly, resulting in flower drop and eventually plant collapse – a loss of impatiens in your garden! Both airborne and overwintering spores meant this popular shade garden flower couldn’t be grown with confidence because of the threat of disease.

At first, gardeners planted alternatives for shade colour: Begonia, Torenia, Coleus, as well as New Guinea Impatiens, which are not susceptible to the disease. But nothing could take the place of the traditional Impatiens walleriana garden fill, colour range and performance.

Beacon Comes To Light

The team at PanAmerican Seed began searching for a disease-resistant Impatiens soon after IDM took hold. Collaborating on the project was a team in The Netherlands, led by breeder Ruud Brinkkemper, and a crew in the United States consisting of product manager Lisa Lacy, plant pathologist Dr. Colleen Warfield, and many others. During numerous plant trials and tests, a selection of Impatiens that displayed high resistance to Plasmopara obducens was discovered and Beacon Impatiens was born!

The International Seed Federation recognizes
two levels of disease resistance:

High Resistance – The plant highly restricts the growth and/or development of the pathogen/damage it causes under normal pressure when compared to susceptible varieties under similar environmental conditions and pressures.

Intermediate Resistance – The plant restricts the growth and/or development of the pathogen/damage it causes but may exhibit a greater range of symptoms or damage compared to high-resistant varieties.

The telltale sign of IDM on the undersides of Impatiens leaves.
Susceptible Impatiens vs. Beacon Impatiens.