Determination of harmful and beneficial mite species in strawberry fields in Ordu and investigation of life table and biological control possibilities of Phytonemus pallidus fragariae Zimmermann (Trombidiformes: Tarsonemidae) and its phytoseiid predators

Fragaria ×ananassa, commonly known as the strawberry, is a perennial plant belonging to the Rosaceae family. Phytonemus pallidus fragariae (Trombidiformes: Tarsonemidae) is a mite species harmful to strawberries. Neoseiulus californicus (Mesostigmata: Phytoseiidae) is an important predatory mite species. This study was conducted to identify mite species in strawberry fields in Ordu Province and to determine the age-stage specific two-sex life tables of P. p. fragariae and native and commercial populations of N. californicus, as well as to explore the biological control possibilities of P. p. fragariae. Between 2021 and 2024, surveys were conducted in wild and cultivated strawberry fields across 13 municipalities of Ordu Province. The age-stage specific two-sex life table parameters for P. p. fragariae and the native and commercial populations of N. californicus were constructed on Albion, Monterey, and San Andreas strawberry cultivars. Non-glandular and glandular trichome density and length were also assessed on the leaves of these cultivars. The distribution of P. p. fragariae was analyzed based on leaf age, surface, and parts, and its relationship with trichomes was examined. In 2023 and 2024, the effectiveness of native and commercial N. californicus at release ratios of 1:10 and 1:20 against P. p. fragariae was researched on Albion, Monterey, and San Andreas cultivars. As a result, a total of 35 different mite species belonging to 9 families were identified in cultivated and wild strawberry areas. The most abundant and common pest mite species was P. p. fragariae, while the most abundant and common predatory mite species was N. californicus. No P. p. fragariae individuals were found in wild strawberries during the study. Survey results indicated that 42.8% of the sampled cultivated strawberry fields were infected with P. p. fragariae. The pest is mostly found on young leaves, followed by fruits, flowers, and medium-aged leaves. The mite did not prefer old leaves. The life table results indicated that P. p. fragariae had the longest pre-adult developmental period, female longevity, and generation time on Albion. The longevity, oviposition time and fecundity of commercial and native N. californicus populations were highest on Albion. The biological performance of NCT was found to be higher than NCY in all three strawberry cultivars. Net reproductive rate (R0), intrinsic rate of increase (r) and finite rate of increase (λ) values of both P. p. fragariae and predators showed no differences among cultivars. Mite numbers were positively correlated with the trichome density, while it was negatively correlated with the trichome length. Studies on biological control demonstrated that native and commercial N. californicus can effectively manage P. p. fragariae populations when released at ratios of 1:10 and 1:20. There was no significant difference in effectiveness between commercial and native populations or among strawberry varieties. The findings are considered to be very important in terms of establishing sampling and control programs in strawberry-growing areas.