Necessity for seasonal monitoring of economically most important pests in different crops, increase input costs of their surveillance. In maize fields, Western corn rootworm - WCR (Diabrotica virgifera sp. virgifera) is economically the most important species and presents a limiting factor for production of maize in continuous cultivation. Its occurrence is usually monitored with pheromone traps. However, as previously mentioned they are time and money consuming due to constant need for field inspections. Since in research projects, finances predefined for weekly inspection of traps are most often non-eligible, there is a need for developing a novel approach for pest monitoring. The use of IT technologies along with commercially available pheromone traps could provide precise information about the situation in traps without frequent field inspections. Also, they are easy to maintain, manipulate and require minimum costs. This work aimed to assess the potential use and the precision of a sensor device with camera, in monitoring the WCR flight on pheromone traps. Sensor device equipped with small camera can capture images of a pheromone trap sticky base and transfer them to a remote server for review, storage and analysis. The main idea in this paper is to present a system that uses a method based on analysis of the image variations of the pheromone pest traps, performed on devices placed in their vicinity which means that sending every image to the server is avoided. In this way, information about the variations in pheromone traps can be found in one location without unnecessarily sending the same images to the server. The obtained results indicate that the proposed method for monitoring the variations of the number of caught specimens on sticky surfaces of pheromone traps, based on the variations of the dark surface on the images, can be a reliable tool in further work.