‘Aggressive infestation’ almost eats away popular Aspen park

The city of Aspen departed from their standard policy of not using herbicides or pesticides when they treated Wagner Park last week to combat an aggressive disease called Ascochyta leaf blight that could have wiped out the turf.

Without the treatment, John Spiess, Senior Open Space and Natural Resource manager, said Wagner Park might not have survived.

“At Wagner, we had this unique situation where we had this fungal attack, and without using something like a fungicide, we potentially risked losing that entire park,” Spiess said. “It can be a really aggressive infestation.”

Wagner Park is a popular destination for pets and their owners, sunbathers, sports games, and more. It’s one of over 30 parks and playgrounds maintained by the city.

While Wagner has never seen Ascochyta before, Spiess confirmed it is a common disease of Kentucky bluegrass lawns in Colorado.

“The disease results in rapid development of large, straw-colored blighted areas of the lawn during the summer,” Spiess said. “The environmental conditions that trigger Ascochyta leaf blight are poorly understood, but we think this was a result of cool and damp temperatures present at Wagner Park.”

An internal team chose a fungicide and used a granular application, which Spiess confirmed is safe for both pets and children as opposed to a spray application. The chosen fungicide, the name of which Spiess did not disclose, treats both the existing fungus and prevents the spread to the entirety of the park.

The granules dissolve quickly with water and are taken up by the roots, according to Spiess. His team estimated that the chosen fungicide has only been used three times in the past 15 years.

The city of Aspen’s strategy is to never get to a stage where using fungicides, pesticides, or herbicides is necessary, hand pulling many invasive species and relying on what Spiess calls “early identification” of pests, funguses, or weeds to then try and change the conditions allowing them to colonize. 

“It highlights that the city really does champion protecting the environment and the ecosystem,” Spiess said. “We only go to the (pesticide) scenario if we feel like it is warranted.”

Without this treatment to Wagner Park, the turf would have been lost, according to Spiess.
“It is safe to say the savings from treating now to replacing the turf later would be significant,” he added.

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