Michigan vegetable crop report – June 30, 2021

Because of current weather conditions, both Downy mildew and Phytophthora are expected to affect cucumbers in Michigan.

“With the field report of downy mildew in Ontario, it is fully expected that the pathogen’s sporangia will be dispersed to Michigan’s growing regions. Our spore trap network has picked up three instances of downy mildew in air samples.”

two images of disease symptoms

Faces of Phytophthora: On the left, soil infested with Phytophthora capsici was splashed onto the crown of the zucchini plant, killing it. On the right, infested soil splashed onto the leaf and petiole of this plant, the whole plant didn’t die (yet). Photos by Ben Werling, MSU Extension.

“Earlier this growing season when field conditions were dry, Phytophthora capsici crown rot was not expected. This situation has now taken a dramatic turn as the recent heavy rains, saturated soils, and high relative humidity have literally created a perfect storm for Phytophthora development and crop destruction.”