Under field conditions where latent Huanglongbing infections may be present, but undetectable by PCR, it is not known whether psyllids transmit low-level infections among trees. New HLB management strategies, such as heat-treating trees (thermal therapy), may reduce pathogen titers in infected trees to low or undetectable levels (Esahni et al.). Heat treatment methods currently under development include enclosing trees underneath tented structure, or applying steam heat directly to tree trunks, for a specific time period such that temperatures rise to approximately 55oC. The objective of this study was to determine how thermal treatment of CLas-infected citrus trees in influenced acquisition of a systemic, circulative infection CLas by the Asian citrus psyllid. Leaf CLas titers were not significantly reduced in infected plants receiving thermal treatment as compared to untreated plants, although numerical reductions in the CLas titers of infected plants occurred during the first sample period following thermal treatment. Similarly, CLas acquisition from infected, thermal-treated trees was not significantly different as compared to acquisition from infected, untreated trees in the field study. Mean adult and nymph acquisition rates were positively correlated with the mean Las titer in leaves. These results suggests that treating the above-ground portion of infected citrus trees at 55�C for 30 seconds is not adequate to reduce acquisition of CLas by psyllids. In a separate greenhouse study, whole tree application of thermal therapy to potted citrus tree resulted in no acquisition from thermal-treated trees compared with 75% of psyllids acquiring CLas from untreated, CLas-positive trees. The replication in this trial was low, and further studies are needed to confirm the efficacy of whole tree thermal therapy on psyllid acquisition; however, the data indicate that whole tree thermal therapy reduces CLas acquisition.