Efficacy of integrated management on control of citrus decline: A case study

Citrus decline has emerged as a serious threat to orchards, particularly in the southern provinces of Iran. To address this issue, a two-year study was conducted in a citrus orchard of jiroft region using a Washington navel variety. The research investigated the impact of various nutritional treatments on mitigating decline, which included: i. control (standard gardening practices as T₁); ii. optimized irrigation, fertilizer and standard management 9 T₂); iii.treatment ii with added potassium silicate (T₃); iv. treatment ii with shade and mulch (T₄); v.treatment ii with mycorrhizae, Trichoderma fungi, fungicides and nematicides (T₅); vi. treatment v with calcium nitrate injection (T₆) and vii. treatment v with calcium nitrate and micronutrients (T₇). The experiment employing a randomized complete block design with three replications. The results revealed a significant difference in yield between different treatments. The control group produced the lowest yield (22.9 kg /tree), while treatment T₄ achieved the highest fruit yield (50.2 kg/tree). Similarly, the final shoot count (spring and summer) was substantially higher in treatment T₄ (191 shoots) compared to control treatment (76 shoots). The statistical analysis confirmed that treatment T₄ exhibited significant improvements across various response variables compared to other treatments. The findings suggested that citrus decline in this region stems from a combination of living (biotic) and non-living (abiotic) stressors. Therefore, a comprehensive approach incorporating optimal irrigation and integrated nutrient management, along with plant mulch in shaded areas and shade netting during the critical period (late June to mid-September), appeared to offer promising solution for mitigating citrus decline in the southern kerman province. Implementing such a holistic strategy deserves serious consideration in order to prolong the productive orchard life, needless to say, no uniform recommendation stands valid across other regions.