Evaluation of application timing and efficacy of the fungicides fluazinam and boscalid for control of Sclerotinia blight of peanut

Abstract

Sclerotinia blight of peanut ( Arachis hypogaea) is caused by the soilborne fungus Sclerotinia minor. Management of Sclerotinia blight of peanut requires an integrated approach that includes rotation with non-hosts, resistant cultivars, cultural practices, and fungicides. Greenhouse experiments compared fluazinam and boscalid and investigated pre- and post-inoculation applications of fungicide or no fungicide to control infections by S. minor. Significant reductions in successful infections in the greenhouse occurred when fungicide was applied prior to, or up to 2 d after, inoculation, but not when applied 4 d after inoculation. Field experiments were conducted from 2004 to 2006 to investigate the comparative efficacy of the fungicides fluazinam and boscalid using alternating sequences of those fungicides or no fungicide for each of three sprays per season. In the field, applications of fungicide that preceded the largest incremental increase in disease incidence provided the best control of disease or increased yield. In both the field and greenhouse studies boscalid performed marginally better than fluazinam. Disease advisories or intensive scouting should be used to determine when epidemics initiate so that a fungicide can be applied prior to infection.