Influence of mechanical and manual pruning on the incidence of pests in 'Clemenules' mandarins.

BACKGROUND: In Spain, citrus pruning is usually done by hand, although mechanized pruning is gradually being introduced as a cheaper alternative. The pruning strategy affects the pattern and intensity of sprouting, and the canopy characteristics, and therefore could affect pest control. In this study, the effect of three pruning strategies on the incidence of key citrus pests was analyzed: manual, mechanical (with hedging and topping) and no pruning (control). In a commercial clementine orchard, sprouting, pest density and fruit damage were evaluated through three seasons. RESULTS: Outside the canopy, mechanically pruned trees had a significantly higher number of shoots, and more shoots were attacked by aphids (cotton aphid, Aphis gossypii, and spirea aphid, A. spiraecola) in comparison with manual or control strategies. Inside the canopy statistically nonsignificant differences were found between strategies. Regarding the pest level of two-spotted spider mite, Tetranychus urticae, and California red scale, Aonidiella aurantii, in general, no significant differences were found between pruning strategies, and in some cases mechanical pruning resulted in a lower level of these pests and fruit damage than manual pruning. CONCLUSION: The density of aphids, which are pests associated with sprouting, was affected by the pruning strategy. However, the densities of T. urticae and A. aurantii and the level of damaged fruit were unaffected. © 2023 Society of Chemical Industry.

Sustainable Use of Pesticide Applications in Citrus: A Support Tool for Volume Rate Adjustment.

Rational application of pesticides by properly adjusting the amount of product to the actual needs and specific conditions for application is a key factor for sustainable plant protection. However, current plant protection product (PPP) labels registered for citrus in EU are usually expressed as concentration (%; rate/hl) and/or as the maximum dose of product per unit of ground surface, without taking into account those conditions. In this work, the fundamentals of a support tool, called CitrusVol, developed to recommend mix volume rates in PPP applications in citrus orchards using airblast sprayers, are presented. This tool takes into consideration crop characteristics (geometry, leaf area density), pests, and product and application efficiency, and it is based on scientific data obtained previously regarding the minimum deposit required to achieve maximum efficacy, efficiency of airblast sprayers in citrus orchards, and characterization of the crop. The use of this tool in several commercial orchards allowed a reduction of the volume rate and the PPPs used in comparison with the commonly used by farmers of between 11% and 74%, with an average of 31%, without affecting the efficacy. CitrusVol is freely available on a website and in an app for smartphones.