Diversity and population dynamics of mites in citrus orchard

The citrus plants are hosts of several species of mites, which cause severe damage to production and quality of fruits in Brazil. The objective of this research was to study the diversity of mites and population dynamics of the main mite species in a citrus orchard, Citrus sinensis (L.) Osbeck, in Descalvado County, State of Sao Paulo, Brazil. Fourteen evaluations were conducted over a period of 12 months, from February 2007 to February 2008. At each assessment, ten leaves and five fruits were collected from the inner part of each citrus canopy, from a total of 40 marked plants. Thirty four mite species were found, which were distributed into 17 families. The most abundant species were: Phyllocoptruta oleivora (Ashmed) (Eriophyidae), Panonychus citri (McGregor) (Tetranychidae), Brevipalpus phoenicis (Geijskes) (Tenuipalpidae) and Fun gitarsonemus sp. (Tarsonemidae). Among the predators, the Phytoseiidae family presented the highest richness (eight species) and the highest abundance (1,072 individuals). Euseius concordis (Chant) was the predominant species, corresponding to 98.3% of the mites of this family. Significant correlations were observed between the population densities of E. concordis and of the phytophagous mites P. citri, B. phoenicis and P. oleivora. Significant correlations were also observed between population densities of these mites and meteorological factors such as temperature and precipitation. The results indicate that E. concordis acts as a natural enemy of P. citri, B. phoenicis and P. oleivora in the citrus orchard.