Time to switch: Managing black streak disorder in celery with cultivar selection

Transplanting susceptible celery cultivars between May 25 and June 15 may result in high incidence of black streak.

Memorial Day weekend has an additional meaning for the Michigan celery industry. That is the time when most celery growers change cultivars that are transplanted in the field. Changing cultivars is currently the most effective strategy for management of a physiological disorder known as “black streak” in celery. This disorder is characterized by black spots in the lower half or throughout the entire length of the petiole (Photo 1). Symptoms occur when hot weather – with air temperatures exceeding 90°F for a couple of days – coincides with the rapid growth stage of celery. Under Michigan conditions, this period now called “black streak high-risk time zone” normally begins on Memorial Day weekend and extends until mid June.

black streak symptoms
Photo 1. Symptoms of black streak disorder in celery

Fortunately, there is a wide range in the susceptibility of celery cultivars to this disorder, with ‘Dutchess’ being the most susceptible cultivar. Currently, cultivar selection is the only effective management tool used by growers. During the period of May 25 to June 15, celery growers who have been planting the susceptible cultivar ‘Dutchess’ are recommended to switch to a more resistant cultivar. For commercial growers, this recommendation has significant implications for identification of the appropriate time to start transplants in the greenhouse.

Readers can refer to the MSU Extension article, Avoiding high-risk period may help prevent black streak development in celery, for more information on celery black streak high-risk time zone.

Dr. Ngouajio’s work is funded in part by MSU’s AgBioResearch.

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