Selection of native microorganisms with potential antagonist Rhizoctonia solani and Phythopthora infestans promoters of minituber growth of papas Solanum tuberosum L. in vitro

Abstract

World agricultural production of potatoes and Andean tubers has been seriously affected by pests and diseases, estimated losses of around 20 to 25 percent. For this reason farmers use synthetic fungicides that can cause resistance to pesticides and generate environmental pollution and toxicity; this problem forced to finding other effective and not harmful alternative methods to combat these pathogens. With respect to potatoes, the fungus Phytophthora infestans is responsible for rancha or late blight (Mont. De Bary) brings estimated at about three billion dollars in annual losses in developed countries, as well as being most responsible for substantial annual expenses by applying fungicides in farming. The objective of the present investigation was to design a biotechnological production process of bacterial biofertilizers from the selection of bacterial strains, in which they managed to isolate and recognition of 4 strains of Azotobacter sp., 2 strains of Azospirillum sp., 7 strains of Bacillus sp.,, 5 of Pseudomonas fluorescens and 2 of Bulkhoderia sp.; these with phosphorus solubilizing activity, nitrogen fixation and antagonist pathogenic fungi; where strains Bacillus sp; Ps. fluorescens-35; Ps. fluorescens-40; Ps. fluorescens-45; Ps. fluorescens -55 and Bulkhoderia cepacia-72, showed a higher activity against Rhizoctonia solani and medium antagonist activity in Phythophthora infestans, potato tuberculillo pathogens isolated from ground and roots of these Andean crops.