PREVENTION AND CONTROL OF Fusarium oxysporum Schltdl. USING BENEFICIAL ORGANISMS IN Pinus oocarpa Schiede ex Schltdl.

The most common disease in forest nurseries is damping-off, commonly caused by the fungus Fusarium oxysporum Schltdl. The objective of this study was to evaluate the effect of a commercial product based on microorganisms (Bactiva®) and a strain of Trichoderma paratroviride Jaklitsch and Voglmayr on the incidence of damping-off and the morphology of Pinus oocarpa Schiede ex Schltdl. plants inoculated with F. oxysporum. A completely randomized design was used, with treatments in an increased factorial arrangement, to evaluate two biological products (a commercial product and T. paratroviride) and three application forms (to the seed, to the substrate, and through irrigation) were evaluated, with an additional control inoculated only with F. oxysporum. The factors revealed that using the commercial product and applying it to the seed reduced the incidence rate to 25 and 23%, respectively. In terms of interactions, the application of the commercial product to the seed, to the substrate, and by irrigation, and with T. paratroviride to the seed and by irrigation, showed the lowest percentage of incidence (<30 %). At 195 days after sowing, T. paratroviride and substrate application improved plant morphology. The interactions showed that the highest root collar diameter (6.5 mm), plant height (23.2 cm), aerial dry weight (3.15 g), total dry weight (4.15 g), and Dickson quality index (0.61) were obtained with substrate-applied T. paratroviride. However, the lowest sturdiness quotient was obtained with the control (3.27), while for root dry weight and aerial dry weight over root dry weight, there were no differences among the treatments evaluated.