ABSTRACT
Population fluctuations of Panonychus citri (Mc Greg.) and the effects of climatic factors, natural enemies and of pesticide treatments on the population of citrus red mite were studied intensively from 1979 to 1984 in Sardinian citrus groves. Seasonal citrus red mite population cycles occurred with maximum population densities in spring and autumn, depending on the seasonal growth cycles of the tree and the direct effects of weather on the mites (cold in winter and hot and dry periods in summer). In the same orchard, grapefruit and lemon trees harboured the higher mite populations in respect to orange and mandarine trees. The most effective predators in approximate order of importance were: phytoseiids (predominantly, Amblyseius stipulatus A.-H.), coniopterygids (Conwentzia psociformis (Curt.)), Stethorus punctillum (Weise) and other several polyphagous coccinellids, Chrysoperla carnea (Steph.) A virus disease was detected in late spring, coinciding with high mite density. High autumn infestations of citrus red mite were noted due to summer treatments against scales with organophosphates, which eliminate the major part of the predators.
