Population dynamics of Raoiella indica (Acari: Tenuipalpidae) and predatory phytoseiid mite in coconut in Puerto Rico

The population dynamics of red palm mite (RPM), Raoiella indica Hirst, was studied in eight locations in Puerto Rico. The selected sites represented different climatic zones and had different densities of host plant. Samples were collected from November 2006 to June 2008. Samples from adult coconut palms (10 leaflets, 3 replicates per site) were washed in 200mL of 80% ethanol, which was then inspected in the laboratory under a stereomicroscope for the presence of red palm mites and for potential phytoseiid mite predators. Mite specimens were slide mounted for species confirmation. Phytoseiid mites, Amblyseius sp., were the most common potential predator observed associated with red palm mites in the palm samples. A PCR-based method showed that the phytoseiid mite feeds on RPM. Variations of the RPM populations among different localities were observed. Comparing the different sites, one saw that the arrival of RPM was followed by an increase in phytoseiid mites. Correlation was statistically significant between the population of phytoseiid mites and the occurrence of red pal mite in coconut.