Bioatividade de subprodutos de capim-limão e proteção do tomateiro, em sistema de cultivo orgânico, contra septoriose

• Autor(a) principal: Santos Neto, José dos
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/1188
• topic: Solanum lycopersicum; Septoria lycopersici; Cymbopogon citratus; Tomate; Doenças e pragas; Septoria; Agroecologia; Ecologia agrícola; Plantas medicinais; Essências e óleos essenciais; Tomateiro; Fungicidas; Brasil.; Sustainability; Solanum lycopersicum; Cymbopogon citratus; Production cost; Brazil.; Ciências Agrárias; Agronomia

Aiming the reduction and rationalization on the use of chemical products to control phytopathogens, the present study had as main objective to evaluate the effect of lemongrass' byproducts (Cymbopogon citratus) (essential oil, crude aqueous extract and citral) on the inhibition of the mycelial growth of Alternaria solani and Septoria lycopersici, on the control of tomato's (Solanum lycopersicum) diseases cultivated at organic system, post-harvest as well as analyze the economic viability of these products. The treatments were: T1 (C. citratus crude aqueous extract - CAE 1%), T2 (CAE 5%), T3 (CAE 10%), T4 (CAE 15%), T5 (C. citratus essential oil- EO 10 μL.L-1), T6 (EO 100 μL.L-1), T7 (EO 200 μL.L-1), T8 (EO 400 μL.L-1), T9 (citral - CI 10 μL.L-1), T10 (citral 100 μL.L-1), T11 (citral 200 μL.L-1), T12 (citral 400 μL.L-1), T13 (control treatment), T14 (bordeaux mixture 1%), T15 (commercial product registered to organic agriculture based on fermented plant extracts) and T16 (tomato cultivated at conventional system), the last used only for the experiment of post-harvest and economic analysis. The in vitro assays were conducted on a completely randomized design with five replicates. The evaluations of the mycelial growth initiated one day after the disk was peaked in the center of the petri dish and lasted until the control took over the entire dish. All byproducts provided significant inhibiting effect on the mycelial growth in both phytopathogens, with linear correlation. S. lycopersici demonstrated to be less sensitive to treatments with the byproducts of C. citratus. The essential oil and its major component, the citral, were superior to treatment with EAB, which, at low concentration and initial assessments, provided stimulation of mycelial growth, indicating the occurrence of the phenomenon known as hormesis. The field experiment was carried out on randomized block design, with four replicates and five plants per plot. It was used the Cordillera cultivar (hybrid F1), intercropped with coriander (Coriandrum sativum). 18 harvests were made and 7 severity evaluations of septoria leaf spot, which occurred naturally in the field. The evaluated variables were: severity (%), area under the disease progress curve (AUDPC), average fruit weight, production (kg) per plant, number of fruits per plant, total and marketable yield, fruit size and defect and diameter of the stem. The severity was affected by the treatments, with T12 and T14 the lowest rates at the final evaluation. The bordeaux mixture had the lowest AUDPC rate, followed by treatments 7, 8, 10, 11 e 12. The total production, as well as the fruit size, weight, number of fruits per plant and the diameter of the stem didn't differ significantly with the treatments. Treatments 7, 8, 10, 12 e 14 to the commercial production and treatments 3, 5, 6, 7, 8, 10, 11, 12 e 14 to fruit defect had a statistical difference which was better than that of the control. The post-harvest evaluation was conducted on completely randomized design, with four replicates and six fruit per plot. It was made physical analysis (color, total and partial weight loss, volume, viability and specific weight), chemical (pH, total soluble solids SST, titratable acidity AT, and ratio) and sensorial (firmness to touch, general external appearance, pulp characteristics, general internal appearance, scent, texture, flavor, odd flavor, sweetness, acidity and global quality). No significant difference was found between most of the organic treatments at the physical and chemical analysis. The most significant difference was observed when comparing the two cropping systems. The tomatoes produced in the conventional system showed less weight loss and pH and those produced in the organic system had a higher ratio and sensory quality. To do the economic viability analysis, the information of conventional cultivation was obtained from a producer at Maringá's region, who used the same cultivar. The conventional system spent 2,33 times more with the phytosanitary management, considering that the number of pulverizations was more frequent than on organic system. The treatment that provided greater financial return was the Bordeaux mixture (T14), that exceeded R$ 7,522.8 to the control and R$ 9,439.6 to the conventional crop system. All by-products of C. citratus treatments provided higher returns than the control and conventional crop systems.