Relative Influence of Rootstock and Scion on Asian Citrus Psyllid Infestation and Candidatus Liberibacter asiaticus Colonization

The citrus industry in Florida faces a destructive endemic disease, known as huanglongbing (HLB), associated with Candidatus Liberibacter asiaticus ( C Las), phloem-limited bacterium, and transmitted by the Asian psyllid (ACP). Rootstocks are regarded critical to keep production commercially viable help trees cope disease. Although most scions susceptible, some rootstocks HLB-tolerant may influence ACP infestation Las colonization therefore grafted tree tolerance. This study aimed elucidate relative of rootstock scion on insect vector under natural HLB-endemic conditions. Seven commercial cultivars different genetic backgrounds were ‘Valencia’ sweet orange Citrus sinensis ) or self-grafted (non-‘Valencia’) planted an open field where abundant. was determined weekly during periods leaf flushing, leaves roots analyzed every 3 months determine titers. Trees more attractive psyllids than non-‘Valencia’ scions. also higher number bacteria larger abundance foliar HLB symptoms. attraction less evident, titers similar regardless rootstock. Among scions, Carrizo had lowest US-942 highest Root varied among cultivars, standard sour harbored trifoliate hybrid such US-942. In trees, detected first 4 after planting, but root remained low throughout study. contrast, increased over time considerably from 7 until end study, 15 planting. Overall, results this demonstrate greater early stages infection. suggests that other cultivar-specific traits, ability tolerate stresses absorb water nutrients efficiently, along influences phenology, play role tolerance later progression.