Riom, J. 1977 [Biological and ecological study of the maritime pine scale Matsucoccus feytaudi, Ducasse, 1942 (Coccoidea, Margarodidae, Xylococcinae) in south-eastern France. III. - Structure of the populations on the tree.]. Annales de Zoologie - Ecologie Animale 9: 709-732.

Notes: Title in English: [Biological and ecological study of the maritime pine scale Matsucoccus feytaudi, Ducasse, 1942 (Coccoidea, Margarodidae, Xylococcinae) in south-eastern France. III. - Structure of the populations on the tree.] In this further part of a series [see RAE/A 66, 2815, etc.], the results are presented of studies on the sectorial and vertical distribution of Matsucoccus feytaudi Ducasse on maritime pine [Pinus pinaster]. The immobile eggs and mobile first-instar nymphs and pronymphs showed a homogenous distribution, but the other stages (the immobile nymphs and the mobile males and females) showed a heterogeneous distribution. The activity of the males varied with the time of day and was dependent on sunshine. The pattern of vertical distribution was dependent on the stage of the insect, the height of the tree and its morphology and the population density of the pest. Fixed nymphs were more widely dispersed than other stages. The largest populations observed were those of nymphs, the density being related to the thickness of the bark. On trees that had only recently been infested, the greater part of the population was found on the bole. On trees infested for some time, the greater part was found on the crown.