Soil health management is a precursor to sustainable control of Phytophthora in macadamia
Different commercial cultivars of Macadamia integrifolia were examined for their relative resistance to Phytophthora cinnamomi in different soil conditions at the seedling stage in the glasshouse and grafted trees under field conditions. Results showed differences in susceptibility to P. cinnamomi exist among macadamia cultivars at both the seedling and tree growth stages. Significant variations were observed in the above-ground parameters (seedling, height and vigour, stem diameter and leaf area). Disease severity in the below-ground parameters (root weight and root volume) was influenced by the level of P. cinnamomi in the soils. Under field conditions, severity of trunk canker and tree dieback was significantly higher in the untreated control trees than trees that were treated once with metalaxyl and potassium phosphonate before planting in the Phytophthora-infested soil. At 4 years after planting, tree height was 40-60% lower in the untreated control trees compared to the trees treated at planting. Possible influence of soil nutrition and effect of rootstock × scion interaction on performance of the scions in soils infested with P. cinnamomi is discussed.
Akinsanmi, O.A. and Drenth, A. (2016). Soil health management is a precursor to sustainable control of Phytophthora in macadamia. Acta Hortic. 1109, 203-208
hypoxia, macadamia, Oomycetes, Phytophthora, Proteaceae, soilborne, tree nut