A bale wrapper apparatus for applying stretch film wrapping to an agricultural bale having a pair of opposed end faces, at least one side surface, and at least one corner where the side surface meets an end face, the apparatus comprising: a table for supporting the bale and rotating the bale about a first axis; at least one film dispenser comprising a holder for a roll of stretch film and a pre-stretcher unit that is configured to pre-stretch the film and apply the pre-stretched film to a bale supported by the table; drive means for applying relative rotation between the table and the film dispenser about a second axis that extends substantially perpendicular to the first axis so that the pre-stretched film applied to the bale forms a bale wrapping that covers the side surface and the end faces of the bale, and a control unit that controls the pre-stretcher unit to adjust the amount of elongation applied by the pre-stretcher unit to the film, characterised in that the control unit is configured to control the pre-stretcher unit such that during at least one single turn of relative rotation between the table and the film dispenser about the second axis, the amount of pre-stretching applied to the film changes repeatedly between a first elongation level and a second elongation level, wherein the first elongation level is greater than the second elongation level, and wherein the control unit is configured to control the pre-stretcher unit such that a part of the film that is to be positioned on a corner of the bale is pre-stretched at the second elongation level, and a part of the film that is to be positioned on an end face or a side surface of the bale is pre-stretched at the first elongation level. a table for supporting the bale and rotating the bale about a first axis; at least one film dispenser comprising a holder for a roll of stretch film and a pre-stretcher unit that is configured to pre-stretch the film and apply the pre-stretched film to a bale supported by the table; drive means for applying relative rotation between the table and the film dispenser about a second axis that extends substantially perpendicular to the first axis so that the pre-stretched film applied to the bale forms a bale wrapping that covers the side surface and the end faces of the bale, and a control unit that controls the pre-stretcher unit to adjust the amount of elongation applied by the pre-stretcher unit to the film, characterised in that the control unit is configured to control the pre-stretcher unit such that during at least one single turn of relative rotation between the table and the film dispenser about the second axis, the amount of pre-stretching applied to the film changes repeatedly between a first elongation level and a second elongation level, wherein the first elongation level is greater than the second elongation level, and wherein the control unit is configured to control the pre-stretcher unit such that a part of the film that is to be positioned on a corner of the bale is pre-stretched at the second elongation level, and a part of the film that is to be positioned on an end face or a side surface of the bale is pre-stretched at the first elongation level.