The best alternative to fumigation depends on the type of pest and infestation level. For termites, localized treatments like baiting systems or spot applications of termiticides can be effective. Heat treatments or steam are alternatives for bed bugs. Biological controls, such as introducing natural predators, are eco-friendly options for other pests. Integrated Pest Management (IPM), which combines preventive measures, monitoring, and targeted treatments, is often the most sustainable and effective alternative to fumigation.