Mite diversity (Acari: Tetranychidae, Tydeidae, Iolinidae, Phytoseiidae) and within-tree distribution in citrus orchards in southern Spain, with special reference to Eutetranychus orientalis

Abstract

Mite diversity of selected citrus orchards in Andalusia (southern Spain) was studied during 2002-2007. The following species were found: Eutetranychus orientalis, Tetranychus urticae, Panonychus citri (Tetranychidae), Tydeus californicus, Lorryia formosa (Tydeidae), Pronematus ubiquitus (Iolinidae), Euseius stipulatus, Typhlodromus phialatus, Neoseiulus californicus, Euseius scutalis, Phytoseiulus persimilis, Paraseiulus talbii and Neoseiulus cucumeris (Phytoseiidae). Eutetranychus orientalis was the dominant tetranychid species in orange and lemon trees, whereas T. urticae was slightly more abundant in mandarines. The most abundant tydeid in clementine and orange was Tydeus californicus, in lemon it was L. formosa. The iolinid P. ubiquitus was found in very low numbers. With respect to phytoseiids, E. stipulatus was dominant in the three citrus species. Eutetranychus orientalis had a unimodal phenology, peaking only in autumn, whereas the other two tetranychids had two maxima. Tydeus californicus showed one or two peaks depending upon the citrus species, and E. stipulatus also had two peaks, one in spring and one in autumn. The mites displayed a non-random distribution in the tree. Eutetranychus orientalis preferred the outer and upper leaves. On the contrary, tydeids (mainly T. californicus) and phytoseiids (mainly E. stipulatus) preferred inner and lower leaves. These preferences had not been sufficiently described previously, and they are important for sampling plans.

Zoophytophagous mites can trigger plant‐genotype specific defensive responses affecting potential prey beyond predation: the case of Euseius stipulatus and Tetranychus urticae in citrus

“…This herbivore uses its stylets to penetrate leaves, either in between epidermis pavement cells or through a stomatal opening, to feed from individual mesophyll cells without damaging the epidermal cell layer . Assuming that E. stipulatus most likely produces a wounding similar to that described for E. scutalis , which also occurs in citrus in the Mediterranean, the plant responses expected after feeding would be different from those triggered by the tetranychid. These differences would be related to the targeted plant cell/tissue type.…”

Plant-feeding may explain why the generalist predator Euseius stipulatus does better on less defended citrus plants but Tetranychus-specialists Neoseiulus californicus and Phytoseiulus persimilis do not

“…Lemon is a cultivated plant on which E. stipulatus is commonly encountered in its native Mediterranean region (Jaques et al 2015;Vela et al 2017). However, Porres et al (1975) could not demonstrate feeding on lemon leaves labeled with radioactive phosphoric acid.…”

Plant defense responses triggered by phytoseiid predatory mites (Mesostigmata: Phytoseiidae) are species-specific, depend on plant genotype and may not be related to direct plant feeding

“…However, as mentioned earlier other potential triggers cannot be excluded. E. stipulatus co-occurs in Spanish citrus orchards with other phytoseiids preying on T. urticae as well (Aguilar-Fenollosa et al 2011;Pérez-Sayas et al 2015;Vela et al 2017); among them, Neoseiulus californicus (McGregor), which can also feed on both prey and plant-derived food (i.e., pollen) (McMurtry and Croft 1997;McMurtry et al 2013), and the Tetranychus sp.-specialist Phytoseiulus persimilis Athias-Henriot. None of these species, though, can directly feed on SO and CM plants (Cruz-Miralles et al 2021).…”