Assessing the Effectiveness of Integrated Treatments against Alternaria alternata in Stevia rebaudiana under Prayagraj Condition of India

Abstract

A field experiment was conducted during the Rabi season of 2022–23 at the Central Research Field of SHUATS, Prayagraj, to evaluate the integrated efficacy of organic manures (FYM @ 4.5 kg/m² and neem cake @ 40 g/m²), a bioagent (Pseudomonas fluorescens @ 2 g/m²), and biomix, applied at two different intervals, in managing Alternaria leaf spot of Stevia rebaudiana caused by Alternaria alternata. This disease poses a significant challenge in stevia cultivation, leading to considerable losses in both yield and leaf quality due to necrotic lessions and premature leaf drop. The experiment was laid out in a Randomized Block Design (RBD) with eight treatments replicated three times. Disease severity was assessed using a standardized 0–5 rating scale, and data were statistically analyzed with significance determined at p ≤ 0.05. The results demonstrated that the combined application of FYM + neem cake + Pseudomonas fluorescens + biomix (Treatment T7) was the most effective, resulting in the lowest disease intensity of 18.56% at 90 days after transplanting (DAT). This treatment also recorded the lowest disease severity at 45 DAT (10.98%), indicating its potential in early disease suppression. The next most effective treatment was the combination of neem cake + Pseudomonas fluorescens + biomix, which showed a disease intensity of 21.85%. These findings highlight the synergistic effect of integrating organic amendments with biocontrol agents in enhancing plant health and managing foliar fungal diseases in stevia. The use of eco-friendly and sustainable disease management strategies like these can play a pivotal role in organic stevia production and improving crop resilience.