Accurate estimation of insect density is essential for effective pest management. A simple robotics and image processing system were combined to automatically recognize the density of whiteflies. Subsequently the robot arm was utilized to spray the pesticides in the area of infestation in a minimized amount. The estimated densities of samples in the laboratory condition were in accordance with the actual values. The detection system was efficient when the whitefly densities were at medium to high levels. The results of the present study indicate that the robotic and image processing integration system described here would be useful for evaluating the population dynamics.