Source: American Phytopathological Society

SUMMARY

Activity of Boscalid, Fenhexamid, Fluazinam, Fludioxonil, and Vinclozolin on Growth of Sclerotinia minor and S. sclerotiorum and Development of Lettuce Drop.
M. E. Matheron, Extension Plant Pathologist and Research Scientist, and M. Porchas, Research Specialist, University of Arizona, Yuma Agricultural Center, Yuma 85364. Plant Dis. D-2004-0412-01R, 2004 (online). Accepted for publication 9 February 2004.

Sclerotinia drop is a major disease of lettuce which is caused by two soilborne fungi, Sclerotinia minor and S. sclerotiorum. Fungicides such as dicloran (Botran), iprodione (Rovral), and vinclozolin (Ronilan) are currently available in the United States to manage this disease. Recently, some new fungicides, including boscalid, fenhexamid, fluazinam, and fludioxonil, have demonstrated efficacy against diseases caused by S. minor and S. sclerotiorum on crops other than lettuce. These studies were conducted to investigate the relative effect of boscalid, fenhexamid, fluazinam, fludioxonil, and vinclozolin on growth of Sclerotinia minor and S. sclerotiorum in agar plate tests as well as control of lettuce drop in the field. In laboratory studies, at a rate of 1.0 µg/ml, all tested fungicides reduced mycelial growth of S. minor and S. sclerotiorum from 87 to 100% and 77 to 100%, respectively. In lettuce plots infested with S. minor, boscalid and fluazinam provided the highest level of disease control, whereas in the presence of S. sclerotiorum, fluazinam, fludioxonil, and vinclozolin were the most efficacious compounds. Boscalid and fluazinam were more effective against lettuce drop caused by S. minor than disease caused by S. sclerotiorum. Boscalid (Endura) is now registered for use on lettuce in the United States.

http://www.apsnet.org/pd/summaries/djn04sum.asp#Matheron