Anthracnose control in orange trees, by pruning, fungicides and a biostimulant

In the Mediterranean, mid-season orange cultivars (8- to 12-month production cycle), are susceptible to anthracnose caused by Colletotrichum sp.
High humidity and mild temperatures during the fruit ripening stage promote pathogen development.
While manual pruning improves canopy ventilation and helps prevent Colletotrichum sp. development, it is costly and time-consuming, prompting some producers to opt for mechanical pruning.
However, mechanical pruning, especially hedging, can stimulate the sprouting and shoots growth on the canopy’s outer part, hindering air circulation, creating optimal conditions for fungal development.
Different treatments have been suggested to control anthracnose in citrus, including the application of fungicides and biostimulants.
This study evaluated the effects of pruning, and three spray treatments on anthracnose control and productivity of orange trees.
Two pruning types were tested: manual and mechanical (hedging on both sides). The treatment with a biostimulant based on seaweed extracts, combined with copper oxychloride and copper gluconate, was also tested.
Mechanical pruning led to more shoots on the canopy’s outer part without reducing production compared to manual pruning.
Anthracnose severity was reduced by copper oxychloride or copper oxychloride with the biostimulant, regardless of pruning type.
Fruit quality and size were similar in all treatments.

XV International Citrus Congress

V. Sustelo, P. Matias, B. Duarte, A. Duarte

algae, citrus, Colletotrichum, diseases, fruit quality, hedging, Mediterranean climate

https://doi.org/10.17660/ActaHortic.2026.1448.68