SOLARIZATION FOR THE CONTROL OF SOIL-BORNE PATHOGENS IN FOREST NURSERIES IN TEMPERATE CLIMATE

Soil solarization was carried out at three eucalyptus forest nurseries in Argentina in order to evaluate an alternative method for controlling damping-off of seedlings. The experiments were performed at forest nurseries, located in a temperate climate (province of Buenos Aires), infected with Fusarium (mainly F. oxysporum) and Pythium species, using single and double layers of transparent polyethylene film during summer months (January and February). Effectiveness of the treatments was evaluated using a biological assay enabling assessment of soil inoculum potential. Soil temperatures reached during solarization at the three nurseries were 44, 45 and 49°C, respectively. The soilborne pathogens were controlled within 4 weeks using a single layer in one of the nurseries and using a double layer in the two others. Although the temperatures generated in the soil were not very high, the results suggest that the antagonistic microflora present in the native virgin soils in Argentina and or biological processes may have contributed to the control of these pathogens.