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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Insects and Horticulture Research » Research » Research Project #444671

Research Project: Therapeutic Molecule Evaluation and Field Delivery Pipeline for Solutions to HLB

Location: Subtropical Insects and Horticulture Research

Project Number: 6034-21000-020-014-A
Project Type: Cooperative Agreement

Start Date: Feb 15, 2024
End Date: Jul 31, 2025

Solutions to solving citrus green disease (HLB) is perhaps the most pressing need in U.S. agriculture. The HLB disease complex, the Asian Citrus Psyllid (ACP) and ‘Candidatus Liberibacter asiaticus’ (CLas) bacterium, has devastated Florida citrus production. The societal impact is massive as thousands of people have lost their jobs, farms and processors have gone bankrupt, and consumer industries inter- connected to citrus industry workers have also been negatively economically impacted. The causative microbe and its insect vector, CLas and ACP, are now found in California and Texas citrus trees. Growers have no options to block transmission of CLas by ACP, and tools are desperately needed in this area. Furthermore, transmission blocking tools must be tailored to the unique needs of the citrus growing states and the needs of juice, fresh fruit, and organic growers. Solutions must include protecting existing and newly planted trees, as well as delivery in an economical format suitable to each industry sector. As an insect-vector borne pathogen, methods to cure the disease in trees or block transmission represent a dead end for the bacteria and a novel solution for huanglongbing in all areas where the insect vector is found. The objective of this research is to conduct field trials to evaluate solutions for citrus greening disease.

We will conduct field testing of molecules that show anti-CLas or anti-ACP activity in greenhouse bioassays. Field testing will be conducted at FlaRes and will include separate trials with bearing trees and newly planted trees in a randomized design. Approximately 800-1000 trees are available. Replicated treatments may direct injection or Symbiont application of therapies. Metrics will include standard measures of tree growth, yield, phytotoxicity, visual symptoms of HLB, and CLas. We expect to implement a molecule testing pipeline that is suitable for evaluating the effects of molecules and citrus genotypes on CLas and psyllids with the most effective ones moved to larger-scale field trials and eventually commercialization.