Citrus canker is a serious disease, caused by Xanthomonas axonopodis pv. Citri bacteria, which infects orange trees (Citrus aurantium L.), leading to a large economic loss in the orange juice production. Brazil produces 50% of the industrialized orange juice in the world. Therefore, the early detection and control of such disease is important for Brazilian economy. However this task is very hard and so far it has been done by naked eye inspection of each tree. Our goal is to develop a new optical technique to detect citrus canker in orange trees using a field portable spectrometer unit. In this work, we will review three experiments on laser induced fluorescence spectroscopy (LIF) applied on citrus canker detection. Our results show that LIF has the potential to be applied on orange plantation with the purpose to detect citrus canker disease.