Chemical methods have been widely used in agriculture to manage pests and diseases. This review provides a comprehensive overview of the chemical methods employed in agricultural practices for pest and disease control. It discusses the different classes of chemical pesticides, including insecticides, fungicides, and herbicides, and their modes of action. The effectiveness of these pesticides against target pests and diseases, as well as the challenges associated with their use, such as resistance development, environmental impact, and human health concerns, are explored. In the realm of insecticides, the classification based on chemical groups and modes of action is discussed. The review examines commonly used insecticides, their efficacy against various pests, and strategies to mitigate resistance. Similarly, the classification and modes of action of fungicides and herbicides are presented, along with their effectiveness and challenges related to resistance development. The review also addresses the concerns associated with chemical pesticide use. Factors contributing to resistance development in pests and diseases are discussed, along with mechanisms of resistance and strategies to manage it. The environmental impact of pesticide use, including effects on non-target organisms, water quality, soil health, and biodiversity, is examined. Human health concerns related to pesticide exposure are also highlighted, along with regulatory measures and safety precautions. Furthermore, emerging trends and alternative approaches are explored. Integrated Pest Management (IPM) principles, which integrate cultural, biological, and chemical control strategies, are discussed as a means to reduce reliance on chemical methods. The potential of biopesticides, including microbial-based and botanical-based formulations, for sustainable pest and disease control is also examined.