Growth Performance and Disease Suppression in Pepper (Capsicum annuum L.) Treated with Trichoderma viride under Fusarium oxysporum and CMV Stress

Abstract

Background: Capsicum annuum (pepper) is an economically important crop whose production is significantly reduced by Fusarium wilt and Cucumber mosaic virus, prompting interest in sustainable control strategies such as the biocontrol agent Trichoderma viride to improve growth and disease resistance. Aim: This study investigated the growth performance of Capsicum annuum L. and the disease suppressive potential of Trichoderma viride under stress conditions caused by Fusarium oxysporum and Cucumber mosaic virus (CMV) in Calabar, Nigeria. Study Design: The experiment was arranged in a Completely Randomized Design (CRD) with six treatments replicated three times. Place and Duration of Study: The research was conducted in the Screen House and Laboratory of the Department of Plant Science and Biotechnology, University of Cross River State, Nigeria, between March and June 2025. Methodology: Seeds of Capsicum annuum L. and sterilized soil on perforated bags were treated with Trichoderma viride before sowing. Fusarium oxysporum and Cucumber mosaic virus were inoculated two weeks after seedling emergence. Plants were maintained in a screen house for 12 weeks, during which growth parameters such as plant height and number of leaves were recorded. Disease severity was assessed using a standard disease rating scale and expressed as disease severity index. Results: Results showed that plants inoculated with Fusarium oxysporum and CMV recorded significant reductions (p ≤ 0.05) in plant height and number of leaves, accompanied by increased disease severity when compared with the control. In contrast, plants treated with Trichoderma viride exhibited significantly improved growth performance and reduced disease severity. The highest plant height (93.56 cm) and leaf production (76.36) were recorded in plants treated with T. viride alone at 12 weeks after inoculation. The highest disease severity (5.00) was observed in plants inoculated with pathogens alone. Combined treatments involving T. viride and pathogens showed moderate growth improvement and reduced disease severity (3.00) compared with pathogen inoculated plants without biocontrol treatment. Conclusion: The findings indicate that Trichoderma viride effectively enhances plant growth and suppresses disease under fungal and viral stress conditions. Its application offers a promising, eco-friendly alternative to synthetic chemicals in the management of pepper diseases. Therefore, the integration of T. viride into sustainable crop production and management systems is strongly recommended for improved yield and plant health in tropical agro ecological zones.