Use of bioactivator associated with fungicides in the management of complex diseases in corn

The positive impact of using bioactivators associated with fungicides in the management of complex diseases in corn.

State-of-the-art systemic nutritional complex, developed with high quality raw materials, which influence the fertilization of flowers and the formation and weight of grains. Cubo IR features amino acids and carboxylic acid in its formulation, compounds that have relevant functions on plant health. It acts in the formation of physical and chemical barriers to the invasion of pathogens. IR Cube acts on the plant in two distinct ways: it increases natural physical resistance through the synthesis of lignin and extensin in the cell wall and chemical resistance by increasing the concentration of hydrolytic enzymes in the cytoplasm. This effect is achieved by Cubo IR in the first fungicide application. The objective of this work was to evaluate the agronomic benefits of using Cubo IR associated with fungicides and the control of helminthosporiosis (Exserohilum turcicum), which can cause losses of up to 50%, when it occurs in times before flowering, and white spot (Pantoea ananatis), bacteria whose leaves with 10% to 20% severity have a 40% reduction in net photosynthetic rate, which also results in a decrease in grain production by about 60% in corn crops.

METHODOLOGY

The corn experiment was conducted by the Spraytec Research and Development team in the municipality of Campo Mourão, Paraná. A randomized block design was used with four replications containing 44 plots measuring 3m wide x 8m long, spaced 0,5m apart. The treatment used as standard was azoxystrobin + cyproconazole and copper oxychloride at commercial and standard doses + Cubo IR at doses of 200ml/ha, 300ml/ha and 400ml/ha, in addition to the control. Applications were carried out at the V8 and V8 + pre-tasseling stages. The severity of white spot was assessed using a diagrammatic scale and the presence of helminthosporiosis symptoms on the leaves. The direct action of treatments on development in T.S.A. (Tryptic Soy Agar) from Pantoea ananatis, the bacterium that causes white spot, and Exserohilum turcicum (synonymy Helminthosporium turcicum) in B.D.A. culture medium. (Potato Agar Dextrose), fungus that causes helminthosporiosis.

RESULTS

In Figure 1, the results of the control (a) standard with fungicide (b) and 200ml / ha of Cubo IR + fungicide (c) are presented, and in Figure 2 the in vitro evaluation of the direct action on the pathogens.

CONSIDERATIONS

The use of Cubo IR associated with fungicides reduced the severity of white spot (Pantoea ananatis) at a dose of 200ml/ha + fungicide in the pre-bolting stage, resulting in a reduction in the bacterial population and the development of symptoms. The evaluation of helminstosporiosis (Exserohilum turcicum (synonymy Helminthosporium turcicum) showed that the fungus is unable to develop in the presence of the treatments applied, inhibiting the vegetative growth of the pathogen.

André L. F. Cuba, Anarelly C. Alvarenga, Caio C. Brunholi, Julio R. Fagliari, Talita Camargo and Sabrina S. Costa