Superficial scald is the most common physiological disorder in apples and pears and causes huge economic losses worldwide. The aim of this study is to determine the different scald susceptibilities of seven pear cultivars/selections during five months of cold storage (CS). Four advanced pear selections and three commercial cultivars were harvested from an orchard located in Emilia-Romagna region, and cold stored at −1 °C and 85% relative humidity (RH).After 90, 120, and 150 days, fruits of each cultivar and selection were removed for ripening for 4 d, after which scald damage, physico-chemical and nutraceutical traits, and enzymatic antioxidant systems were evaluated on peel and pulp. ‘Abbé Fétel’, ‘Falstaff’, and ‘CREA 171’ did not showed superficial scald symptoms after 90 days, while ‘Doyenne du Comice’ and ‘CREA 264’ showed the highest susceptibility. After 90 days, CS ‘Falstaff’ and ‘CREA 179’ showed the highest total polyphenol content (TPH) in peel, followed by ‘Doyenne du Comice’ and ‘AbbéFétel’; lowest TPH was detected in ‘CREA 264’. After 120 and 150 days of CS, ‘Abbé Fétel’ and ‘CREA 171’ showed the highest peel TPH. ‘CREA 264’ and ‘CREA 125’ reached the lowest values of TPH during the three CS time periods. Superoxide dismutase and catalase activities were higher in the peel of scald-resistant than that in scald-susceptible pear cultivars/advanced selections. Superficial scald induced an increase in polyphenoloxidase, and guaiacol peroxidase activities involved in fruit-browning during CS. Furthermore, we observed an increase in lipoxygenase activity and consequent membrane damage in both the peel and flesh of the fruit. This study indicates that pear cultivars/advanced selections have different superficial scald susceptibilities that enable them to induce the activity of several antioxidant enzymes, following CS.

Peach and apricot trees usually set more fruit than they can adequately support. Crop load adjustment through fruit thinning is a routine practice adopted by fruit growers to obtain a marketable product. However, hand thinning is an expensive, labor-intense operation. The interest in the mechanization of thinning has increased in the last decades. A new machine, consisting of a tractor-mounted rotor equipped with elastic rods radially inserted on a central axis, has been recently developed to thin both flowers and green fruits in stone fruit crops. In order to test its effectiveness and optimize the operative conditions, trials were carried out in 2016 in two apricot and two peach commercial orchards located in the northeast Italy. Tests were carried out on narrow-canopied orchards, during blooming time, and on green fruit, assessing the flower and fruit removal percentage and the labor saving as compared with the standard fruit hand-thinning practice. In apricot, the machine removed 20.8% of flowers and 43.6% of fruit, allowing 48% time saving in the follow-up fruit manual thinning as compared with the control (hand-thinning only). In peach, mechanical thinning at blooming time removed 63% of flowers, allowing 42.4% time saving in the follow-up fruit manual thinning as compared with the control, whereas mechanical thinning of fruit at the beginning of pit hardening stage removed less than 10%. The development of a mechanical thinning practice, complemented by a manual finishing, could represent a valuable near-term solution to reduce thinning labor time.

As a result of mechanical fruit-thinning tests on various peach trees, difficulties in fruit detachment from branches were found for some cultivars. For this reason, and to create a database of the required detachment forces, the relationship between detachment and angle at which force is applied to the fruits was studied. The study was carried out in a peach orchard sited in Forlì, on four peach cultivars when the fruits were 20–40 mm in size. Using a dynamometer, the force required to detach fruits was measured, and different angles were evaluated to simulate the various ways in which the thinner hits fruits. The analysis of the different angles showed that, on average, fruits are detached more easily if the force is applied with a 90° angle respective to the fruit position on the branch. On the other hand, if the force is applied with an angle of 0°, the average force required is three times higher. The study highlighted that adaptability to mechanical thinning is higher in some cultivars than in others. The results also showed that it is important to consider the impact angle of the thinner on fruits when evaluating the efficiency of the thinner machine.

In this study, the thinner machine with yellow rod equipment was tested in relation to tree branch length and orientation in April 2019, in a narrow-canopied apricot orchard of Emilia Romagna Region, Italy. The trees were mechanically thinned with manual finishing, and comparative tests were carried out simultaneously with the ordinary hand thinning (control). Three groups of two plants were identified as replication for a total of six plants per row. Three rows were checked, considering field uniformity average. The branches were grouped into four classes according to their length: 90 cm. Branch inclination on the plant, radial or longitudinal with respect to the row, was evaluated. Fruit number before the thinning, after the first and the second machine intervention, after three days of the mechanical thinning and after the hand finishing was recorded. This experience showed satisfactory results in terms of thinning efficiency and reduced damage to both fruits and branches, as a function of the class length and insertion point in the main branch of the plant. Thinning efficiency was always kept above 37% of the left load after hand finishing, and on average between the treatments close to 44%. Fruit damages always remained below the economic thresholds to marketable production or to the plant.

ISHS VI International Strawberry Symposium EFFECTS OF PLANTING DATES ON STRAWBERRY PLUG PLANT PERFORMANCE IN SICILY