Techniques for Reducing the Abundance of Spring–Summer Flush Shoots in Southern Spanish Orange Orchards

Abstract

The Mediterranean Basin is the second highest citrus growing region in the world behind China. Citrus trees are known to produce several flush shoots per year, particularly during the spring–summer season. Farmers endeavor to reduce the growth of summer shoots by means of hand pruning, especially those located at the top of the tree, as most of these shoots become vigorous, nutrient consuming, non-productive, and attractive to several pests. Furthermore, hand pruning substantially increases the costs of citrus orchards production. This research was therefore intended to study new different treatments to control spring–summer flush shoots and thus reduce growers’ investments in citrus production. Six different treatments were applied in two experimental and high density orange orchards over two consecutive years: (1) control; (2) topping (mechanical pruning); (3) dichlorprop-p; (4) triclopyr; (5) topping + dichlorprop-p; and (6) topping + triclopyr. The treatment of dichlorprop-p alone reduced the number of summer young shoots in both years. Moreover, these applications did not negatively affect yield or fruit quality. These mechanical methodologies help citrus growers manage the density of flush shoots and reduce hand labor costs in citrus orchards.