Dispersal of mites within apple trees of an abandoned orchard in Central Utah

From January to July, 1967, a study of dispersion and distribution characteristics of Typhlodromus mcgregori Chant, Bryobia praetiosa Koch, and Bryobia rubrioculus (Scheuten) was made in an abandoned apple orchard in Highland, American Fork, Utah and in the laboratory at Provo, Utah. Bryobia praetiosa overwintered on the spurs and the other protected sites and with the advent of spring migrated out of the tree and back onto the cover crop. Coinciding with the movement of B. praetiosa out of the tree was the hatching of winter eggs and maturation of B. rubrioculus primarily on the spurs but as far down the trunk as ground level. By the middle of June, B. rubrioculus completely replaced B. praetiosa on the spurs and leaves. The effectiveness of T. mcgregori as a control agent upon B. praetiosa and B. rubrioculus is limited because of the differences in their distribution during their active stages.