Influence of pest management systems on diversity and abundance of phytoseiid mites (Acari: Phytoseiidae) in Florida citrus orchards

Six citrus orchards under three different pest management systems, conventional, organic, and untreated, were surveyed to determine the abundance and diversity of phytoseiid mites in south and central Florida. Sampling was conducted in the canopy, ground cover, and leaf litter from April 2019 to February 2021. A total of 1,778 specimens of 27 species were identified. There were 13 species from the canopy, 15 from the ground cover, and 18 from the leaf litter with some common species among these habitats. In the tree canopy, Typhlodromalus peregrinus (Muma, 1955) (39%), Euseius mesembrinus (Dean, 1957) (25%), and Iphiseiodes quadripilis (Banks, 1904) (19%), were the dominant species. Species richness and Shannon Index were higher in organic (4.25 and 0.89, respectively), and untreated (5 and 0.98, respectively) systems compared to conventional (3.25 and 0.68, respectively). More phytoseiids were observed in the canopy under conventional systems (mean of 68 specimens per sample) compared to organic and untreated (35.5 and 34.5 respectively). Typhlodromalus peregrinus (43%), Typhlodromips dentilis (De Leon, 1959) (25%), and Proprioseiopsis mexicanus (Garman, 1958) (13%) were dominant in the ground cover. There was no significant difference in phytoseiids abundance and diversity across pest management programs. In the leaf litter, Amblyseius curiosus (Chant & Baker, 1965) (26%), Proprioseiopsis carolinianus (Muma, Metz, & Farrier, 1967) (15%), and Chelaseius floridanus (Muma 1955) (14%) were the dominant species. Shannon Index was significantly higher in conventional groves (1. 33) compared to organic and untreated groves (0.86 for both). Results, spray schedules, and ground cover management will be discussed.