EARLY DETECTION OF HUANGLONGBING (HLB) IN NURSERY TREES FOLLOWING INFESTATION WITH ASIAN CITRUS PSYLLID (ACP)

This is a study to determine the time from when a nursery plant is exposed to an Asian citrus psyllid (ACP) to when the bacteria associated with huanglongbing (HLB) can be detected and to provide a management tool for nurserymen. Two recent developments make this trial feasible: 1) the discovery that the bacteria associated with HLB may be detected early in roots, and 2) the further development of our Smart-DART¿ LAMP assay so that the sensitivity of detection is consistently two logs greater than real time quantitative PCR. Nursery trees found infested with ACP are subject to long term quarantine, suspension and cancellation of registration. The research will provide information as to how early HLB could be detected from nursery trees following infestation with infectious ACP using qPCR and the more sensitive LAMP assay. The results of this research will provide documentation of when HLB can be detected in plants once exposed to infectious ACP, and determine if there is an effect in ability to detect HLB due to different rootstocks. Nursery plants of various scions and rootstocks will be exposed to infectious ACP once, then maintained in a greenhouse for protections and following practices normally used for budwood increase blocks. At bi-monthly intervals, the roots, mature leaves, and young leaves will be tested using the Smart-DART¿ LAMP assay for HLB compared to the standard protocol qPCR protocols, and monitored for symptom development.