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 analysed: manual, mechanized (with hedging and topping) and no pruning. In a commercial clementine orchard, sprouting, pest density and fruit damage were evaluated along 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 non-pruning strategies. Inside the canopy not statistically significant 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 mechanized 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. On the contrary, the density of T. urticae and A. aurantii and the level of damaged fruits were not affected. This article is protected by copyright. All rights reserved.