Citrus advisory system: A web-based postbloom fruit drop disease alert system

•Decision support system to monitor and predict the risk of postbloom fruit drop on citrus.•Reducing the fungicide applications following the recommendations of the system.•Using leaf wetness and temperature to predict disease outbreaks on citrus. Postbloom fruit drop (PFD) is a severe fungal disease of citrus that causes fruitlets to fall off trees prematurely and is linked to wet weather during bloom. Florida growers have recently struggled with PFD outbreaks, especially during the spring of 2015. The PFD control is usually done with calendar-based applications that may not be required if environmental conditions do not promote the development of PFD. The objective of this study was to develop a web-based tool to assist citrus growers with spray decisions for managing PFD risk in Florida. Information technologies such as databases, queries, and programming languages have been used to develop this tool. The system collects weather data from the Florida Automated Weather Network (FAWN) and weather stations installed by the AgroClimate research group, and uses weather observations to run a PFD disease model and estimates the environmental favorability for infection. The system sends notifications to farmers according to the risk and recommends fungicides to be applied based on the specific PFD risk and flowering stage. The tool developed under this research is available to Florida growers under the University of Florida AgroClimate information and decision support system.