Post-bloom mechanical thinning for can peaches using a hand-held electrical device

Abstract

Hand thinning is a necessary but costly practice in peach (Prunus persica L. Batsch) production. A hand-held mechanical device has been tested to thin peach trees, trained in “free Italian vase”, 50–62days after full bloom. Hand thinning (HT); mechanical thinning (MT); mechanical and hand thinning (MHT); and un-thinned (UT) were tested from 2008 to 2011 in Murcia, south-eastern Spain. After thinning, the distance between the remaining fruits was measured: the shortest distance was 5.2cm for MT, with no significant differences between MHT and HT at 8.6 and 8.8cm, respectively. The differences in distances did not affect the yield and size of the fruit at harvesting in any of the cases. There were no significant differences between HT, MT and MHT treatments in fruit per tree, mean fruit weight and yield efficiency in the 4years the test lasted. Farmers considered the hand-held mechanical device positively because it increased field efficiency. Moreover, with HT the operating time was 291hha−1, with MHT it was 87hha−1 and with MT, 27hha−1. The most expensive system was HT (2442€ha−1) as opposed to 824€ha−1 for MHT. The lowest cost was for MT with 296€ha−1. The net value of fruit (€ha−1) showed no significant differences between HT, MT, and MHT. Based on our study, MT appears to be a promising technique for thinning peach trees for the canning industry, because although the reduction of production costs is not high in comparison with the total cost of the crop, the increase in work speed is of great interest to thin the trees on the most appropriate dates.