The purpose of this work is to understand how the citrus black spot pathogen (phyllosticta citricarpa) spreads within and between citrus groves , specifically by determining (1) how long the…

The Department of Agriculture Animal and Plant Health Inspection Service awarded the University of Florida Division of Sponsored Research a cooperative agreement valued at $166,886 on September 30, 2026, to research the spread of citrus black spot pathogen (Phyllosticta citricarpa) within and between citrus groves in Florida.

The research comprises two primary experimental components: determining how long the pathogen's conidia survive on agricultural equipment in the presence or absence of plant debris and testing the effectiveness of sanitizers at reducing conidia viability; and assessing whether conidia from symptomatic dropped fruit can move upward into the citrus canopy under natural field conditions. The recipient will integrate these findings into a quantitative risk assessment model predicting the likelihood of pathogen transmission via contaminated equipment or dropped fruit. The work is designed to inform regulatory decisions, sanitation guidance, and quarantine strategies to slow citrus black spot spread in Florida and protect citrus production and trade.

The period of performance runs from September 30, 2026, through September 29, 2027, with all work performed in Florida.

The purpose of this work is to understand how the citrus black spot pathogen (phyllosticta citricarpa) spreads within and between citrus groves , specifically by determining (1) how long the pathogen's conidia can survive on agricultural equipment in the presence or absence of plant debris and how effective different sanitizers are at reducing their viability, and (2) whether conidia from symptomatic dropped fruit can move upward into the citrus canopy under natural field conditions. The project will integrate these experimental findings into a quantitative risk assessment model that predicts the likelihood of pathogen transmission via contaminated equipment or dropped fruit. Ultimately, this work is intended to inform and improve regulatory decisions, sanitation guidance, and quarantine strategies to slow the spread of citrus black spot in florida and protect citrus production and trade.