Furanocoumarins in Florida celery varieties increased by fungicide treatment

Florida celery cultivars Florida 2-14, Florimart, M9, Florida 296, M68, and Junebelle contained total psoralen + bergapten + xanthotoxin + isopimpinellin ranging from about 12 to 50 mu g/g. Treatment of the commercial Florida cultivar 2-14 with Brave 500, Manzate-D, or Kocide 101 fungicides increased bergapten 2-4 times in leaves and stalk, xanthotoxin 2-3 times in stalk, and isopimpinellin about 2-3 times in leaves but did not increase psoralen levels. These increases represent increased calculated biological activity toward human skin. This is the first report of fungicide induction of furanocoumarins in celery.