BIOTECHNOLOGICAL APPROACH TO THE BIOLOGICAL CONTROL OF COUCH GRASS (CYNODON DACTYLON) USING MAIZE SMUT FUNGUS (USTILAGO MAYDIS) UNDER FIELD CONDITIONS

ISSN: 3030-3931, Impact factor: 7,241 Volume 10, issue 1, Oktabr 2025 https://worldlyjournals.com/index.php/Yangiizlanuvchi worldly knowledge OAK Index bazalari : research gate, research bib. Qo’shimcha index bazalari: zenodo, open aire. google scholar. Original article 395 BIOTECHNOLOGICAL APPROACH TO THE BIOLOGICAL CONTROL OF COUCH GRASS (CYNODON DACTYLON) USING MAIZE SMUT FUNGUS (USTILAGO MAYDIS) UNDER FIELD CONDITIONS Atajanova Gulzar Nagmetovna [email protected] Field: Plant Biology Research Methods: Theoretical, Experimental, and Observational Abstract:This study investigates the potential use of the maize smut fungus (Ustilago maydis) as a natural biological control agent against couch grass (Cynodon dactylon) in cotton and agricultural lands. The fungus spores were applied at 35°C through moist spraying during the flowering stage of the weed. The infection gradually spread through the floral tissues into the vascular system, inhibiting growth and ultimately leading to the suppression of couch grass populations. Over a five-year observation period, 0.5 m² treated plots resulted in suppression and elimination of couch grass in up to 12 m² surrounding area. Introduction Couch grass (Cynodon dactylon) is a perennial weed that significantly reduces crop yield and soil nutrient availability in cotton, wheat, and maize cultivation. Chemical herbicides used to manage this weed are costly and can cause ecological imbalance by damaging beneficial soil microorganisms and contaminating water systems. Therefore, the development of an environmentally friendly and sustainable approach is a key focus in plant biology and agricultural biotechnology. Smut fungi, particularly Ustilago maydis, known for causing smut disease in maize, have been studied for their potential as natural biocontrol agents. Materials and Methods Field experiments were carried out in cotton-growing regions where couch grass was dominant. The fungal culture of Ustilago maydis was prepared in laboratory conditions using sterile maize extract medium. The spores were harvested, suspended in distilled water, and adjusted to a concentration of 10⁶ spores per milliliter. During the flowering phase of couch grass, the suspension was sprayed over 0.5 m² of land under controlled humidity (70–80%) and temperature (35°C). Observations were recorded weekly for five years to assess the impact on growth, reproduction, and spread. Results and Discussion The treated areas showed significant inhibition of couch grass growth within the first two months. By the end of the first growing season, infected plants displayed stunted growth, chlorosis, and reduced seed production. Within three years, the density of couch grass decreased by more than ISSN: 3030-3931, Impact factor: 7,241 Volume 10, issue 1, Oktabr 2025 https://worldlyjournals.com/index.php/Yangiizlanuvchi worldly knowledge OAK Index bazalari : research gate, research bib. Qo’shimcha index bazalari: zenodo, open aire. google scholar. Original article 396 80%, and after five years, it was completely eradicated in a 12 m² radius from the treatment plot. Laboratory analysis revealed that fungal hyphae penetrated the vascular tissues, disrupting nutrient flow and gradually weakening the host plant. The findings suggest that biological agents like smut fungi can serve as sustainable alternatives to chemical herbicides. Furthermore, integrating fungal biocontrol with traditional agricultural practices can enhance soil health and maintain ecological balance. Conclusion The results confirm that Ustilago maydis can be effectively used as a biological control tool against Cynodon dactylon in agricultural systems. The controlled application during the flowering stage ensures deep fungal penetration and long-term suppression of weed populations. This approach represents a promising direction in plant biology and sustainable agriculture, minimizing chemical usage while promoting ecological safety. Future research should focus on identifying optimal spore concentrations, understanding long-term soil interactions, and ensuring environmental safety of fungal applications. References: 1. Agrios, G. N. (2005). Plant Pathology. Academic Press. 2. Strange, R. N., & Scott, P. R. (2005). Plant disease: A threat to global food security. Annual Review of Phytopathology. 3. Martínez-Espinoza, A. D., García-Pedrajas, M. D., & Gold, S. E. (2002). The Ustilaginales as plant pests and model systems. Fungal Genetics and Biology. 4. Snyman, M. C., et al. (2019). Biological weed control: Principles and practice. Weed Research Journal.