Application of defence inducers reduces the severity of Black Sigatoka (Pseudocercospora fijiensis) in Musa acuminata AAA Cavendish

Abstract

Banana production is threatened by Black Sigatoka disease caused by the fungus Pseudocercospora fijiensis (M. Morelet) Deighton, which is considered one of the most destructive diseases of this crop. Black Sigatoka control primarily relies on the use of chemical fungicides, which increases production costs and may have negative impacts on health and the environment when applied inappropriately. In addition, their extensive use may select for resistant strains, causing reduced efficacy of fungicides. Therefore, alternative control options for Black Sigatoka are urgently needed. In the present study, we evaluated plant resistance inducers as an alternative for disease management. The effect of resistance inducers on the growth and development of P . fijiensis and on banana defence-related gene expression was measured. Banana plots were treated with five resistance inducers and the best three were included in a commercial programme of Black Sigatoka management. Each resistance inducer, either applied individually or mixed with standard fungicides, showed significant reductions of Black Sigatoka severity when compared to the control. It was confirmed that resistance inducers reduced in vitro growth and development of P . fijiensis as shown for other pathogens. Banana defence-related genes were found to be up-regulated after application of resistance inducers. These results suggest that the reduction of disease severity in banana crops after application of resistance inducers may be due to a direct effect on P. fijiensis in addition to the activation of plant responses. Resistance inducers are a potentially effective alternative to Black Sigatoka disease management.

Bibliographic Information