ABSTRACT
The predators Cryptolaemus montrouzieri L and Nephus réunioni FÜRS were used in a grapefruit grove, with a view to one of the two applications of chemicals usually used in Crete to control Planococcus citri RISSO by biological control techniques. Substitution of the second, June, application by predators yielded satisfactory results in that the density of the P. citri population never exceeded the economic infestation threshold. By contrast, high densities were observed when the first, May, application was replaced by predators, thus showing the need for this application. Application of chemicals in both May and June kept citrus mealy bug populations under control, whereas the use of biological means alone resulted in high Pl. citri populations throughout the period.
