Vegetative and productive response of olive trees under anti-insect nets

Anti-insect netting can help control pests in many fruit tree crops while reducing the application of pesticides. In olive production, netting is used as a method of controlling the fly Bractrocera oleae Gmel., especially for table cultivars. In addition to preventing the direct damages to the fruits by excluding the insects from access to the canopy, the net can be useful in mitigating other abiotic stressors. For example, it can provide shade that protects fruits from excessive insolation leading to greater final growth. In this study we evaluated the shading effect of anti-insect nets on the vegetative and reproductive growth of the olive tree. In July 2021 and 2022, nets with a shading factor of 15% were installed in two treatments: before and after the pit hardening (15 days difference). Uncovered trees were used as control. In 2021, the trees did not show differences regarding the fruit yield, but the trees covered with the nets after the pit hardening had bigger fruits than the control without nets. The installation of nets after pit hardening also induced a higher number of nodes in the vegetative portion of 1-year-old mixed shoots during the period following the installation of the nets (from July to October 2021). In 2022 no differences were recorded among the applied treatments and the control, probably because of a low crop load of the trees. Further investigation is needed to understand the optimal installation time so as to not negatively affect vegetative-reproductive growth and flower induction.