Integrated Strategies to Reduce Botryosphaeriaceae-Associated Dieback in Avocado Under Mediterranean Climatic Stress

Avocado (Persea americana Mill.) is gaining economic relevance in Mediterranean regions such as southern Spain. In recent years, production has been severely affected by dieback caused by Botryosphaeriaceae species, a problem intensified under drought conditions. Conventional chemical control has shown limited effectiveness due to the scarce availability of fungicides and the difficulty of targeting pathogens colonizing lignified tissues. This study therefore evaluated eco-friendly control strategies comparing their performance with conventional fungicides and complementary cultural practices within an integrated management framework. Varietal tolerance significantly influenced symptom development and yield, with younger trees (1–2 years old) being more susceptible. Among the tested treatments, potassium silicate (K-Link) was associated with moderate reduction in disease intensity, with decreases in disease index ranging from 5–10%. Other products, including the biostimulant Brotolom® SOILFORCE (BTL) and the disinfectant Huwa San® TR50, also showed reductions in disease severity (approximately 5% and up to 14%, respectively), although their effects varied depending on cultivar and season. Cultural practices such as autumn pruning reduced symptoms and improved yield but required greater economic and labor inputs. In contrast, gibberellic acid was highly effective, reducing flowering, improving canopy balance, decreasing dieback incidence by 28%, and increasing yield by 34%. Integrating eco-friendly products, particularly potassium silicate, with targeted cultural practices and gibberellic acid application provides effective and sustainable tools to mitigate avocado dieback under Mediterranean conditions.