Lemongrass byproducts for tomato septoria leaf spot control in organic crop system

Abstract

The present study aimed at evaluating the efficiency of lemon grass byproducts (Cymbopogon citratus) at the control of tomato diseases by experiments in vitro and in vivo. The in vitro assay consisted of the following treatments: crude aqueous extract (CAE) at concentrations of 0, 10, 50, 100 and 150 g.L^-1, essential oil (EO) and citral (CI) at concentrations of 0, 10, 100, 200 and 400 μL.L^-1, on the mycelial growth of Alternaria solani and Septoria lycopersici. All byproducts provided significant inhibiting effect on the mycelial growth in both phytopathogens, with the best results being obtained by the highest concentrations of OE and CI. In the in vivo assay plants were sprayed seven times over the cycle with the same concentrations of lemongrass’ byproducts used in the in vitro test, with the addition of control treatment (application of water), Bordeaux mixture 1% and commercial product Crop-set (Improcop®). For the prevention and control of septoria leaf spot, as well as for larger commercial fruit production the best option was the use of Bordeaux mixture 1%, then the largest essential oil concentrations of C. citratus and citral. The Lemongrass’ byproducts had direct antifungal effect and demonstrated potential for use in control disease of tomato grown in organic production system