Cercospora leaf spot disease is one of the most diseases causing great losses in sugar beet yield which causes by Cercospora beticola fungus. The anti-fungal effective of three plant extracts in growth of Cercospora beticola have been determined by the thermal imaging of colony temperature and linear growth curves of the fungus. In vitro study three plant extracts Haloxylon spp, Chicory Cichorium spp and Capparis spp were used with different concentration to inhibit the linear growth of Cercospora beticola. All plant extracts with high concentration inhibited fungal growth of Cercospora beticola and increasing the colony temperature of Cercospora beticola whereas with the low concentration of three plant extracts the colony temperature was lower but relatively higher than the colony temperature of control which not treated with plant extracts. Results revealed that the use of the thermal imaging offers an alternative method to identify the interaction between plant extracts and linear growth of Cercospora beticola. Moreover; it could apply this technique as anew innovative approach in plant pathology field.