We built passive spore traps and deployed six in an Immokalee area grove with a history of citrus black spot and three in the Lake Alfred, CREC groves that do not have a history of black spot. The traps were installed at the heights of 0.5, 1.0, and 1.5 m. The goal was to determine if passive traps could capture enough Guignardia spp. ascospores to serve as a detection method to monitor for the spread of G. citricarpa prior to disease expression. The disease is often not detected for years after the fungus is introduced to the grove. In our study, we were not able to detect many Guignardia spp. ascospores with the passive traps. When compared to the Burkard style spore trap that has a flow of air across the tape used to trap the ascospores of 10 L/min, there was at least a 10 fold reduction in ascospore counts. We were able to establish that there is no difficulty in extracting DNA from G. citricarpa conidia on the silicone coated slides so if a sufficient number of ascospores were detected, then qPCR could be used to identify the species and approximately how many without the tedium of counting spores. While we were not able to capture enough ascospores to declare the trap design a success, there is some promise and perhaps with a different trap design this could be a useful tool in ascospore monitoring.