Abstract

RODRIGUEZ-ROMERO, Víctor Manuel; VILLANUEVA-ARCE, Ramón; TREJO-RAYA, Ariadna Berenice  and  BAUTISTA-BANOS, Silvia. Chitosan and Pseudomonas fluorescens extracts for Alternaria alternata control in tomato (Solanum lycopersicum). Rev. mex. fitopatol [online]. 2019, vol.37, n.2, pp.202-219.  Epub Sep 30, 2020. ISSN 2007-8080.  https://doi.org/10.18781/r.mex.fit.1812-2.

Alternaria alternata is a fungus that causes damage to the tomato crop, it is characterized by producing black spots and wilting in plants and fruits; synthetic fungicides are the main tools to control this fungus. The objective of this study was to evaluate the effect of the application of mixtures of chitosan and extracts of Pseudomonas fluorescens in the control in vitro of A. alternata on mycelium and conidia, as well as the incidence and severity in greenhouse tomato plants. The use of the mixture of chitosan 1.5% (w/v) + extract of P. fluorescens 50% (v/v) resulted in 60 and 100% of in vitro inhibition of mycelial growth and conidia germination of A. alternata respectively. In greenhouse, the plants were inoculated with A. alternata, later they were sprayed with the mixture of chitosan 1.5% (w/v) + extract of P. fluorescens 50% (v/v) every 7 days until flowering. The incidence was 100%, while the severity was 51.8 and 38.9% for 7 days and 16.9 and 16.2% for 60 days, respectively. The mixture used is an option for the control of A. alternata.

Keywords : antifungal activity; biological control; incidence; severity.