Potencial de productos a base de fosfitos en el control de Pythium sp. en condiciones in vitro

O objetivo deste trabalho foi avaliar o potencial de produtos a base de fosfitos de potássio, cobre e manganês no controle de Ptyhium sp. em condições in vitro. O experimento foi conduzido no laboratório de fitossanidade da Universidade Tecnológica Federal do Paraná, campus Dois Vizinhos. O delineamento foi inteiramente casualizado com quatro repetições, sendo a unidade experimental constituída por uma placa de Petri®. Os fosfitos foram adicionados nas concentrações de 0,001; 0,002; 0,004; 0,006% ao meio de cultura BDA (Batata, Dextrose e Agar), corrigido o pH do meio com NaOH até pH6,0, e então, vertidos para as placas de Petri® onde foram inseridos discos de 5mm, com micélio fungo no centro da placa. As placas foram acondicionadas em incubadora B.O.D à 25° com fotoperíodo de 12 horas, por um período de 12 dias, quando obteve-se o crescimento micelial até atingir as bordas das placas da  testemunha.  Os resultados observados demonstraram haver um efeito fungistático significativo entre as concentrações dos produtos e o crescimento micelial, sendo que com o aumento das concentrações ocorreu uma redução do crescimento micelial do Pythium sp.. Na concentração de 0,006% ocorreu uma ação fungicida, não havendo o crescimento do patógeno, demonstrando a eficácia dos mesmos no controle in vitro de Pythium sp.El objetivo de este trabajo fue evaluar el potencial de productos a base de fosfitos de potasio, cobre y manganeso en el control de Ptyhium sp. en condiciones in vitro. El experimento fue conducido en el laboratorio de fitosanidad de la Universidad Tecnológica Federal de Paraná, campus Dois Vizinhos. El delineamiento fue completamente casualizado con cuatro repeticiones, siendo la unidad experimental constituida por placa de Petri. Se añadieron los fosfitos a las concentraciones de 0,001; 0,002; 0,004 al medio de cultura BDA (Patata, Dextrosa y Agar). corregido el pH del medio con NaOH hasta pH6,0 y entonces drenados para las placas de Petri donde se insertaron discos de 5 mm, con micelio de lo hongo en el centro de la placa. Las placas fueron acondicionadas en incubadora B.O.D a 25 ° con fotoperíodo de 12 horas, por un período de 12 días, cuando se obtuvo el crecimiento micelial hasta alcanzar los bordes de las placas del testigo. Los resultados observados demostraron un efecto fungistático significativo entre las concentraciones de los productos y el crecimiento micelial, siendo que con el aumento de las concentraciones ocurrió una reducción del crecimiento micelial del Pythium sp. En la concentración de 0,006% ocurrió una acción fungicida, no habiendo el crecimiento del patógeno, demostrando la eficacia de los mismos en el control in vitro de Pythium sp.The objective of this work was to evaluate the potential of products based on potassium, copper and manganese phosphites in the control of Ptyhium sp. under in vitro conditions. The experiment was conducted at the Phytosanitary Laboratory of the Universidade Tecnológica Federal do Paraná, Dois Vizinhos campus. The design was completely randomized with four replicates, with the experimental unit consisting of a Petri® plate. The phosphites were added at concentrations of 0.001; 0.002; 0.004; 0.006% to the BDA (Potato, Dextrose and Agar) medium, corrected the pH of the medium with NaOH to pH 6.0, and then poured into the Petri® plates where 5mm discs were inserted with fungal mycelium in the center of the board. The plates were conditioned incubator B.O.D at 25 °C with 12-hour photoperiod for a period of 12 days, when the mycelial growth was obtained until reaching the edges of the control plates. The observed results showed a significant fungistatic effect. Among the concentrations of the products and mycelial growth, with the increase of the concentrations a reduction of the mycelial growth of Pythium sp. At the concentration of 0.006%, a fungicidal action occurred, without the growth of the pathogen, demonstrating their efficacy in the in vitro control of Pythium sp

Chitosan in the induction of resistance to the damping off tomato seedlings caused by Rhizoctonia solani Kuhn

The objective of this study was to evaluate the potential of chitosan in the damping off tomato resistance induction caused by Rhizoctonia solani. The tomato seeds were submerged in solution with chitosan for twenty minutes in concentrations of 0.25; 0.5; 1 and 2% and in the control (distilled water only). The seeds were sown in polystyrene trays containing substrate inoculated with R. solani and kept in a growth chamber with 12 hours photoperiod and temperature of 25 ºC ± 2 °C for 14 days. After this period we evaluated the survival of seedlings, length and fresh weight and activity of the enzyme phenylalanine ammonia lyase (PAL), chitinase and β-1,3-glucanase. The results showed that chitosan when applied to the treatment of tomato seeds at a concentration of 0.30%, favoring the survival of seedlings inoculated with the pathogen substrate. This result is mainly related to the activation of resistance mechanisms in the plant, evidenced by activation of FAL enzymes, chitinase and β-1,3-glucanases.The objective of this study was to evaluate the potential of chitosan in inducing resistance against damping off in tomato caused by Rhizoctonia solani. The tomato seeds were submerged in solution with chitosan for 20 minutes in concentrations of 0.25%; 0.5%; 1% and 2% and in the control (distilled water only). The seeds were sown in polystyrene trays containing substrate inoculated with R. solani and kept in a growth chamber with 12 hours photoperiod and temperature of 25 ± 2 ºC for 14 days. After this period we evaluated the survival of seedlings, length and fresh weight and activity of the enzyme phenylalanine ammonia lyase (PAL), chitinase and β-1.3-glucanase. The results showed that chitosan when applied on tomato seeds at concentration of 0.30% incresead the survival of seedlings growing in substrate inoculated with the pathogen. This result is mainly related to the activation of resistance mechanisms in the plant, evidenced by activation of PAL, chitinases and β-1.3-glucanases enzymes