Controle de Alternaria Solani em tomateiro com óleo essencial de pitangueira

Abstract

The tomato (Lycopersicon esculentum Mill.) is one of the main vegetables of economic value in the world. Features extensive history of problems, responsible for production losses, such as black paint caused by the fungus Alternaria solani. Thus, the objective of this work was to evaluate the alternative control of tomato by using black paint of the essential oil of Surinam Cherry (Eugenia uniflora L.). The experiments were conducted at the Universidade Federal da Fronteira Sul, Campus Laranjeiras do Sul under laboratory conditions and vegetation. The fungus was obtained from fruits of tomato infected and isolated in the laboratory of plant pathology, potato dextrose agar medium in (BDA). The suspension of conidia concentration used was adjusted to 1 x 104 conidia mL-1 in hemacitômetro. The Mycelial growth experiment was conducted in Petri dishes with BDA containing concentrations (0.01%, 0.05%, 0.1%, 0.5% and 1%) and essential oil of germination of spores was real. To evaluate the effect of essential oil in vivo test was carried out in a greenhouse, in tomato plants, at concentrations of 0.01%, 0.05%, 0.1% and 0.5%. For evaluation of the activity of defence-related mechanisms were performed analysis of peroxidase biochemical, polifenoloxidase, phenylalanine ammonia-lyase, total protein and carbohydrate. The essential oil was diluted in distilled water containing 0.1% Tween 20. The experiments were conducted in fully randomized design 5 repetitions. OE promoted significant inhibitory effect on Mycelial growth, germination of spores and size of germinativos tubes, especially in higher concentrations. OE promoted a reduction in number of lesions of the black paint from the concentration of 0.01%. There was also an increase in the activity of linear peroxidases, polifenoloxidases and total protein in leaves treated as not having been treated, indicating local and systemic effect. These results indicate the potential of essential oil of Surinam to control paints in black tomato plants.