Riaui, Muhammad Amin NL2021-08-242021-08-242020-10wahyu sari yenihttps://repository.unri.ac.id/handle/123456789/10131The number of diseases in areca plants makes betel nut farmers confused in determining or choosing the right and suitable type of treatment for the areca plant. This is what makes it difficult for farmers to get good and maximum betel nut fruit because they cannot make a proper diagnosis of the betel nut plant, which causes the quality and productivity of the betel nut to decline and it can cause the incomes of betel nut farmers to drop. A web-based expert system can be used to help solve problems in terms of assisting each farmer in making diagnoses for handling betel nut diseases appropriately and effectively. The method used in diagnosing diseases in areca plants is the Certainty Factor Method, where this method will analyze based on the symptom data entered by the user so that a result of disease identification in the betel nut plant is obtained in the form of disease name, level of certainty and how to handle it. The system that is built is expected to be able to help farmers solve medical problems in areca plants so that they can get high-quality and high-quality betel nuts.enExpert SystemsCertainty Factor MethodAreca PlantsAreca PlantsArticle