Avoiding losses due to black streaking disorder in celery
Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.
For the last two years, celery growers have suffered severe economic losses due to a new physiological disorder named “black streaking.” The disorder makes the entire crop unmarketable. With celery being one of the most intensive and high value crops (about $8,000/A in 2005), many growers were severely affected because of the high production costs. To our knowledge, this was the first report of black streaking in celery. The cultivar ‘Dutchess’ was more affected than other cultivars. With most celery producing regions being affected, due to the unmarketable finished product, the farmers had to incur substantial monetary losses.
Celery plants with this defect look perfectly healthy in the field; however, when cut, some petioles show “black streaks” in the lower half or throughout the entire length of the petiole. Symptoms in large plants were more pronounced than in smaller ones.
The problem is a physiological disorder, and is not caused by a pathogen. Studies conducted in 2006 showed that the symptoms can be triggered under field conditions by high temperatures. The number of petioles with black streaking symptoms increased as temperature in our experiment was increased. The cultivar Greenbay exhibited high levels of tolerance to the disorder.
Tips for avoiding losses in 2007
In both 2005 and 2006, black streaking occurred on celery plants that were in their exponential growth phase (active growth) during the month of July. Both 2005 and 2006 weather data indicate that during that time air temperatures exceeded 90ºF for a couple of days.
With a zero tolerance for this problem in 2007, growers should be particularly careful in programming and scheduling their crop. Our current suggestion, based on the 2005 and 2006 experience are as follows:
- Minimize the acreage of the susceptible varieties for planting between May 25 and June 15.
- During that window of time use a tolerant variety like ‘Greenbay.’
Dr. Ngouajio's work is funded in part by MSU's AgBioResearch.