Submitted to: Annual Cumberland Shenandoah Fruit Workers Conference
Publication Type: Proceedings
Publication Acceptance Date: February 1, 2006
Publication Date: February 20, 2006
Citation: Miller, S.S. 2006. Thinning the pillar peach tree growth habit with a spiked-drum shaker or chemical bloom thinners. Annual Cumberland Shenandoah Fruit Workers Conference. Vol. 81., Pg 187-192. 2006 Technical Abstract: Hand thinning standard growth habit peach trees is a very costly, but necessary task. Mechanical devices to aid in thinning have been developed, but none have proven highly efficient and capable of completely replacing hand thinning. Pillar peach trees have a very upright growth habit and offer new opportunities to examine mechanical methods for peach thinning. This study was designed to evaluate a spiked-drum shaker, developed for orange harvesting, for thinning pillar peach trees. Two bloom thinning materials, ammonium thiosulfate (ATS) and a contact non-selective herbicide (Matran 2 EC, 50% clove oil) were included in the test for comparison. The spiked-drum shaker traveling at 2 or 3 km/hr removed an average of 254 fruit per tree and reduced the number of fruit that was needed to be removed in follow-up hand thinning. Hand thinned control trees required an average of 455 fruit to be removed to obtain adequate thinning. Mechanical thinning increased fruit size at harvest compared to all other treatments. However, the mechanical spiked-drum shaker plus follow-up hand thinning to space remaining fruits resulted in overthinning and a significant reduction in crop load. ATS and Matran 2EC applied as bloom thinners were ineffective in reducing crop load. Fruit on ATS thinned trees was larger than fruit on non-thinned control trees. Despite the overthinning in the spiked-drum treatments, this method appears to have promise for thinning upright growth habit peach trees, but additional studies are needed to achieve optimum crop load and fruit size responses.