2019 ASHS Annual Conference

Panama disease caused by Fusarium oxysporum f. sp. cubense (FOC) is the most destructive disease in banana production. In this study, we explore a potential non-chemical approach to reducing the incidence of Panama disease in fields in Taiwan. Fresh materials collected from 11 naturalized or invasive plants were subjected to steam-distillation, and the isolated essential oils or hydrosols were subsequently evaluated for in vitro antifungal activity against three FOC reference isolates: YJL-F040 race 1, ATCC-76243 race 2, and ATCC-38741 subtropical race 4. The essential oil of the Biden pilosa plant demonstrated potent antifungal activity against FOC isolates, showing 22% to 43% inhibition of mycelial growth in races 1, 2, 4, and 70% inhibition of spore germination in race 4. A preliminary field experiment was then conducted in an orchard in Taitung County, Taiwan, and the area was divided into four sections, and one testing area and three control areas were randomly assigned. A re-dissolved 0.01% (v/v) solution prepared from the essential oils and hydrosol of B. pilosa plants were irrigated into the bulk soil areas of 84 banana plantlets during secondary hardening, once a week beginning March 13, 2017. The incidence of Panama disease was investigated from August 28 to November 15, 2017. Disease incidence was just 16% in the testing area, compared to 53%, 51%, and 12% in the three control areas. A second investigation was carried out on four different orchards from March 20, 2018 to December 21, 2018. Incidence rates of Panama disease were 22.2% to 27.3% in the testing areas and 45.2% to 62.2% in the control areas. In-depth analysis of the antifungal compounds in B. pilosa essential oils was carried out with gas chromatography–mass spectrometry (GC-MS). Our results suggest a promising non-chemical approach for controlling the occurrence of Panama disease using B. pilosa essential oils.