Relationships between environmental factors and level of mycorrhizal infection of citrus on four islands in the Eastern Caribbean

Abstract

Citrus root and soil samples were collected from the Caribbean islands of Barbados, Dominica, Grenada, and St Lucia. The roots were examined for the presence of vesicular-arbuscular mycorrhizal (VAM) fungi and the soil samples analysed to determine pH; percentage of organic matter; and Ca, Mg, K, N, P, S, B, Cu, Fe, Mn, and Zn contents. The age of the trees sampled, the altitude of each site, and its annual rainfall were also recorded. The significant correlations found between measures of VAM fungal infection and site characteristics varied between islands. For each island, multiple regression equations were developed to predict levels of VAM fungal colonization of the roots on the basis of site characteristics. Plant health and degree of V AM fungal infection were related; the healthiest plants were the most highly colonized.