Phytoseiid mite assemblages and Dialeurodes citri (Hemiptera: Aleyrodidae) infestations in persimmon orchards under different soil managements

The whitefly Dialeurodes citri, is considered one of the two most important persimmon pests in Spain. Insecticide management is the most common practice for its control. Persimmon trees are known to shelter abundant phytoseiid mite assemblages, which could contribute to the biological control of whiteflies. The use of cover crops of Festuca arundinacea to enhance phytoseiid abundance and its effects on D. citri incidence is under study. In this work, both phytoseiids and whiteflies were sampled from tree canopies of 15 years old persimmon groves located in the region of La Ribera Alta (province of Valencia). Four groves had this cover crop and the other four bare soil management during 2021 growing season. Phytoseiids were also sampled from F. arundinacea. Samplings were conducted every 14 days beginning on the 19^th of April. Groves with F. arundinacea cover crops were sown on October 2019 and they are mowed four times per year on February, April, June and October. Phytoseiid abundance in persimmon canopies of groves with cover crops is 1.3 times higher than in those of bare soil groves. Species composition and their relative abundance (Euseius stipulatus: 80% of the captures; Typhlodromus phialatus: 20%) is nevertheless similar. Five species (Proprioseiopsis messor, Neoseiulus barkeri, N. californicus, T. phialatus and E. stipulatus) have been found on F. arundinacea. Whitefly immatures abundance was on the average 3.1 times higher in persimmon leaves of groves with bare soil than with cover crops. Results suggest that F. arundinacea cover crops may contribute at enhancing biological control exerted by phytoseiids.