Occurrence and Population Dynamics of Mites Associated with Citrus Trees at Menoufia Governorate

Abstract

Population dynamics and species composition of phytophagous and predatory mites in citrus orchards were determined from January to December 2016 at Shenofa locality, Shebin El-Kom, Menoufia governorate, Egypt. The survey revealed the occurrence of phytophagous mites as: Panonychus citri (McGregor), Eutetranychus orientalis (Klein) (Tetranychidae); Phyllocoptruta oleivora (Ashmed) (Eriophyidae); Brevipalpus californicus (Banks) (Tenuipalpidae) and Tydeus californicus (Banks) (Tydeidae), representing the most common phytophagous species found in citrus orchards. In addition, two predatory mite species of two families were recorded as: Amblyseius swirskii Athias-Henriot (Phytoseiidae) and Agistemus exsertus Gonzalez (Stigmaeidae) were found to be the most abundant predatory species inhabiting citrus leaves. The population fluctuation of phytophagous and predacious mites on studied citrus varieties was varied according to citrus varieties and sampling dates reaching its highest peak, in most cases, during September. Navel orange recorded the highest numbers of P. oleivora in comparison with other varieties of citrus (290.31 indiv. /10 leaves), while the highest number of P. citri and B. californicus were 85.63 and 45.3 indiv. /10 leaves on Balady orange. The obtained result indicated that the maximum and minimum temperature and relative humidity expressed as an insignificantly positive during 2016 season on the population of P. oleivora, E. orientalis, B. californicus, T. californicus, A. swirskii and A. exertus, but highly significance difference was obtained between population of P. citri only. Finally, it could be concluded that winter months are suitable for applying different biological control agents including predatory mites where pests are lowest in numbers and the optimum environmental factors are present as well.