Potentialities of floristic species from the Nipe-Sagua-Baracoa massif for the control of tomato phytopathogenic fungi

Abstract

The biological activity of extracts obtained from Citrus paradisi and Citrus aurantium on strains of phytopathogenic fungi that affect tomato cultivation was studied. For this, in vitro bioassays were developed to evaluate the effect of ethanolic extracts on the mycelial growth of the fungi Fusarium oxysporum, Sclerotium rolfsii and Alternaria solani. The zonal inhibition method was used in plates, by seeding mycelial discs in inverted form, in Petri dishes with Papa-Dextrose-Agar medium (PDA). The extracts at the 15% concentration were deposited in perforations made in the medium and the plates were incubated at 24 ° C for 120 hours. The evaluations were carried out every 24 hours for 5 days and consisted of measuring the growth of the colonies. A significant inhibition was observed in the growth of the Sclerotium rolfsii strain, the causative agent of tomato wilt. A completely randomized design with a factorial arrangement was used, the variation factors being the strains and the plant extracts. Each treatment was replicated 3 times with control water or ethanol treatments as appropriate. The data were subjected to Analysis of Variance and the means were compared using the Student Newman Keuls test (p <0.05).