Using iNaturalist observations to detect disease in Red Mangroves (Rhizophora mangle)

Detection of disease over broad spatial scales is important to managing the spread of many diseases. One way to do this is to work with citizen scientists to collect data over broad spatial and temporal scales. Citizen science observations are becoming more widely available through web and app interfaces such as iNaturalist.org. iNaturalist.org provides passive sampling of organisms through photographs with a geolocation. These observations are often used to examine biodiversity and species monitoring, but, disease detection is also possible. Here, I demonstrate the utility of using iNaturlist.org observations of red mangrove to detect foliar disease symptoms such as lesions. I downloaded observations of red mangrove from iNaturalist.org, filtered them and examined images for foliar disease symptoms. Out of 153 filtered images, I found that 42% showed no signs of foliar disease while 58% did show foliar disease symptoms. I also found that observations of red mangrove were recorded from 15 countries in total, with 11 countries having at least one observation with foliar disease symptoms present. While small, this study demonstrates the utility of using resources such as iNaturalist.org to obtain preliminary disease observations which can be used to further focus in person disease surveys and sampling.