Soil solarization in combination with organic matter for the control of Pythium spp.

The objective of this work was to evaluate the effect of soil solarization in combination with sewage sludge, chicken litter and Pinus bark added to soil for the control of Pythium spp. Two field experiments with chrysanthemum and cucumber were carried out in two soils: one commercially cultivated with chrysanthemum and in the other artificially infested with Pythium spp. The effects of the treatments were evaluated by measuring electrical conductivity, pH, microbial activity of soil as well as shoot growth and root fresh weight of chrysanthemum plant. The chicken litter induced suppressiveness to the pathogen due to higher soil temperatures, enhanced electrical conductivity, and increased microbial activity, which was evaluated by diacetate fluorescein hydrolysis and CO2 emission. On the other hand, the sewage sludge and the Pinus bark did not induce pathogen suppressiveness. Solarization did not affect plant shoot growth nor root fresh weight of chrysanthemum plants, but it significantly controlled the pathogen in the experiment with cucumber.