Multi-study analysis of the added benefits of combining soil solarization with fumigants or non-chemical measures

Soil solarization (SH) is a non-chemical method in which solar heating is used to manage a wide range of soilborne pests. We analyzed several independent studies to assess the efficacy of SH in suppressing a wide range of soilborne pathogens in different agrosystems and under various climatic conditions, and to quantify the added value of combining SH with chemical or non-chemical measures. We analyzed 69 documented experiments and calculated the level of pest management efficacy by SH alone or in combination with either fumigants, organic amendments or biological agents. The analyses were clustered into three groups of soilborne pathogens: (i) various species and formae speciales of Fusarium; (ii) root-knot nematodes; (iii) a group consisting of the pathogens Sclerotium cepivorum, Verticillium, Pyrenochaeta, Rhizoctonia and Pythium. Combining SH with additional measures improved management efficacy, reduced the variance between experimental results, increased the percentage of cases with high management efficacy and reduced the percentage of cases with low management efficacy, compared to SH alone. The efficacy of SH combined with additional measures was not significantly affected by the initial disease pressure. Yield increase in the Fusarium group was positively correlated with disease control efficacy, and the combined measures produced the upper values. These results demonstrate the benefit of combining SH with other control measures in managing soilborne pathogens.