Submitted to: International Citrus Congress Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 7/31/2012
Publication Date: 11/8/2012
Citation: Deng, X., Guan, L., Liang, M., Xu, M., Xia, Y., Sequeira, R.A., Chen, J. 2012. Heat treatment of Huanglongbing–affected citrus trees in field for reduction of “Candidatus Liberibacter asiaticus”. International Citrus Congress Proceedings. p.207. Interpretive Summary:
Technical Abstract: Huanglongbing (HLB, yellow shoot disease) is a devastating citrus disease worldwide. Research conducted by Lin Kung-Hisang et al. in 1960s China suggested that heat treatments were effective at eliminating the pathogen that causes HLB from scions. We tested the effects of high temperature on the reduction of “Candidatus Liberibacter asiaticus” (CLas) titers in HLB-affected citrus trees in Guangdong, China. Heat treatments were delivered via covering a tree with a temporary enclosed tent of plastic sheeting, which used natural sunlight to raise ambient temperature. Twenty-four sweet orange trees with HLB symptoms in an orchard were divided into six blocks. Three blocks of four trees received heat treatments and the other three blocks served as controls. Heat treatments were performed three times in August with temperature exceeding 38 C for three hours each time. Leaf samples were collected in the following months and real-time PCRs with primer set HLBasf/HLBasr and TaqMan probe HLBp were used to monitor CLas titer changes. For three consecutive months (October, November, and December), average percentage reduction in CLas titer from heat treated trees was 85.0, 83.3, and 85.2. In contrast, average percentage reduction in CLas titer for untreated control trees was 19.0, -12.7, and 25.0 for the three months. Further evaluation is underway to confirm the efficacy of plastic sheeting heat treatment for controlling HLB.