08 Aug 2019 --- Researchers have found a fast and low-cost staining method to diagnose one of the most serious citrus plant diseases, Citrus Huanglongbing (HLB), potentially helping to mitigate crop loss. The method identifies insect feeding sites, which are the transmission agent. The sites can then be tested for the causal agent (Candidatus Liberibacter asiaticus) using a quantitative real-time polymerase chain reaction. This allows HLB to be identified up to two days after transmission, instead of the months traditionally needed.