Incorporation of Microorganisms to Reduce Chemical Fungicide Usage in Black Sigatoka Control Programs in Costa Rica by Use of Biological Fungicides

Abstract Control of Black sigatoka, one of the most destructive diseases affecting the banana industry worldwide, requires frequent chemical fungicide treatments, thus greatly increasing production costs. Due to increasing pathogen resistance to fungicides and negative environmental impacts, alternative control methods need to be incorporated into management programs. Spores of Bacillus subtilis, Trichoderma harzianum, and an extract of Saccharomyces cerevisiae (Agro-Mos®), all biological pesticides were rotated with traditional chemical fungicides (chlorothalonil and mancozeb). It was possible thereby to reduce the total chemical pesticide use by 25%. To determine the effects under different climatic conditions, the first trial was conducted during the wet season and the second trial during the dry season. Disease severity was recorded, every week for 20 weeks, in all plants during each trial. In all treatment groups, disease severity was significantly lower (P