In the first six months of this project, we investigated the influence of several limiting factors on the performance of a ground penetrating radar (GPR) to accurately detect HLB-affected citrus roots and determine their main structural characteristics. First, single-factor experiments were conducted to evaluate GPR performance. Factors evaluated were: (i) root diameter; (ii) root moisture level; (iii) root depth; (iv) root spacing; (v) survey angle; and (vi) soil moisture level. Second, two multi-factor field experiments were conducted to evaluate the performance of the GPR in complex orchard environments. Experiments were conducted at the citrus research grove of the University of Florida Southwest Florida Research and Education Center (SWFREC) in Immokalee, FL, USA.According to the GPR work principle, three subsystems must be investigated at the outset for accurate root detection: (I) the tree root system; (II) the soil system; and (III) the GPR system. In this study, three types of limiting factors were studied: (1) root property (root diameter and root water content); (2) root position (root depth, horizontal and vertical distance between roots) and scan direction; (3) soil property (soil type and moisture). Four �output� parameters were evaluated: (i) the shape of the hyperbola; (ii) the signal strength; (iii) the signal overlap and interference, and (iv) the signal noise.Upon root detection, the GPR generated a hyperbola in the radar profile; from the width of the hyperbola, the diameter of the root was successfully determined when roots were larger than 6 mm in diameter. The GPR also distinguished live from dead roots, which is indispensable for studying the effects of soil-borne and other diseases on the citrus tree root system. If two or more roots are located in close proximity, the GPR can distinguish the roots only if their horizontal distance is larger than 10 cm and their vertical distance is larger than 5 cm. The results demonstrated that GPR is useful for studying citrus tree root systems under southwest Florida growing conditions.Furthermore, we started developing an automated (remote-controlled) platform for the GPR technology. The current GPR technology requires an operator to manually complete 360-degree peripheral scans around the tree trunk (per tree) to cover the entire rooting system. A wheel encoder measures and records the distance covered by the GPR. This manual procedure generates many errors (�noise�), mainly because it is difficult for the operator to follow a �perfect� circular path (360-degree peripheral scan) around the tree (for more information please check our preliminary work at Derival et al., 2018). This automated system will increase data collection accuracy and decrease data collection time. The first prototype is ready for field trials.�In the next quarters, we will:1)� � � � �A �GPR evaluation� manuscript is under preparation. We will submit it to a high-quality peer-reviewed journal.�2)� � � � �Evaluate the remote-controlled prototype in the field. Based on the evaluation metrics, we will develop further and improve the first prototype.In this activity, we will compare the �automated GPR� collected data and the developed 3D maps with the actual root systems of citrus trees. First, we will generate the 3D maps using the automated GPR; then, we will excavate the trees to compare the developed maps with the actual root system. This activity will be limited to non-commercial experimental trials in place at SWFREC.