Evaluation of the impact of two citrus plants on the variation of Panonychus citri (Acari: Tetranychidae) and beneficial phytoseiid mites.

ABSTRACT

The abundance of Panonychus citri McGregor 1916 (Acari Tetranychidae) and its associated enemies (Euseius stipulatus Athias-Henriot, 1960; Typhlodromus sp.; Phytoseiulus persimilis Athias-Henriot, 1957) was studied on two 12-year-old citrus cultivars, specifically Clementine "Nules" (Citrus Clementina) and Valencia (Citrus sinensis), in the Gharb region of Morocco. Throughout the entire monitoring period in the Valencia late cultivar, the density of the spider mite P. citri on leaves was notably higher at 38.0% (n = 1,212 mobile forms). Predator P. persimilis exhibited a leaf occupancy of 25.0% (n = 812), followed by Typhlodromus sp. at 20.0% (n = 643). Conversely, the abundance of E. stipulatus was lower at 17.0% (n = 538). In the Nules variety, P. citri abundance recorded a higher percentage at 48.0% (n = 1,922). E. stipulatus emerged as the most abundant predator at 23.0% (n = 898), followed by P. persimilis with 16.0% (n = 639). Meanwhile, the population of Typlodromus sp. remained notably low at 13.0% (n = 498). Regarding the fluctuation of the different mites studied on the two cultivars across monitoring dates, the period from May 4 to June 1 was characterized by low temperatures and a diminished presence of mite populations (P. citri, E. stipulatus, Typhlodromus sp., and P. persimilis). However, from June 7 to June 19, characterized by high temperatures, a notable increase in the presence of mite populations was observed. As regards the effect of the variety on the different mites studied, the varietal impact was significant.