Abstract: A vine stabilizing attachment for a vine row crop upright harvester comprises a pair of support beams configured for mounting on opposite sides of the infeed throat portion of the harvester, the support beams mounting a stabilizer apparatus arranged to engage a portion of a vine row forwardly of the shaker mechanism of the harvester and support said forward portion of the vine row against movement during shaking of vines rearwardly thereof by the shaking mechanism of the harvester. The stabilizer apparatus may be pairs of rods, or plates arranged to press vines between them to prevent them from shaking while adjacent rearward vines are being shaken to harvest the fruit. The stabilizer apparatus alternatively may be vine wire dampener rollers arranged to bear against the vine wire forwardly of the portion of the vine row being shaken.