Leaf wetness sensors - a comparative analysis

Leaf wetness duration (LWD) is an important variable in plant disease prediction, which can promote the germination of fungal pathogen spores on leaf surfaces. There are different types of leaf wetness sensors (LWS) to measure LWD with no broadly accepted measurement standard. This paper performs a comparative analysis of various LWS that are commonly used in commercial stations. The sensors used in the experiment have different size, shape, and working principles. Visual observation were made and a sensor response time test was performed to evaluate sensors´ performance. Using a dielectric constant to measure leaf wetness was shown to be more effective than resistance-based sensors.