Oligonychus perseae Tuttle, Baker & Abbatiello (Acari: Tetranychidae) population dynamics and associated phytoseiid mites (Acari: Phytoseiidae) in avocado orchards in the Canary Islands (Spain)

ABSTRACT The Persea mite, Oligonychus perseae, was identified for the first time in the Canary Islands (Spain) in 2006 becoming a major pest in avocado crops. This study analyses seasonal trends of Persea mite and phytoseiid predatory mites. The study aims to gain a better understanding of pest-predator dynamics and assess which predators have potential as biological control agents. In addition, predatory mites present in resident wild ground cover were studied with a view to promoting biological control. Results showed that Persea mite was present year-round with one or two peaks from April to July. The incidence of O. perseae varied depending on the avocado production area, but in all of them, it exceeded the density of 100 mites/leaf, established as the action threshold. Phytoseiids were more abundant on the trees in late winter, spring and early summer. Euseius stipulatus, Neoseiulus californicus and E. scutalis represented almost 96.5% of phytoseiids collected in commercial avocado orchards. They were also the most abundant species in the untreated study site. Resident wild ground cover associated with commercial avocado orchards was composed of 45 plant species belonging to 22 families, with Urticaceae and Asteraceae harbouring the highest richness in phytoseiid species.