Title: Resistance of poncirus and citrus x poncirus germplasm to the Asian citrus psyllid Authors
Submitted to: International Research Conference on Huanglongbing
Publication Type: Proceedings
Publication Acceptance Date: December 5, 2013
Publication Date: February 6, 2013
Citation: Richardson, M.L., Hall, D.G. 2013. Resistance of poncirus and citrus x poncirus germplasm to the Asian citrus psyllid. In: Proceedings of the International Research Conference on Huanglongbing, February 4-8, 2013, Orlando, Florida. Interpretive Summary: The Asian citrus psyllid, which is a worldwide pest that spreads citrus greening disease, may best be controlled by finding varieties of citrus that are resistant to the psyllid. We tested trifoliate citrus and trifoliate hybrids for resistance to the psyllid. Trifoliates were nearly all resistant, and some hybrids also were resistant. We are currently working to identify chemical volatiles produced by the plants that may influence host plant selection by the psyllid, and so far we have found differences in volatiles between resistant and susceptible plants.
Technical Abstract: The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, has spread to citrus growing regions nearly worldwide and transmits phloem-limited bacteria (Candidatus Liberibacter spp.) that are putatively responsible for citrus greening disease. Host plant resistance may provide the most effective control, but ACP has a broad host range and resistance in Citrus and relatives to ACP has not been widely documented. Very low abundances of ACP were found on two accessions of Poncirus trifoliata L. in a field survey. Therefore, we tested whether 81 accessions of P. trifoliata and xCitroncirus sp. (hybrids of P. trifoliata and Citrus spp.) from the USDA-ARS National Clonal Germplasm Repository for Citrus and Dates were resistant to ACP by determining whether these accessions influence oviposition and lifespan of adults in no-choice tests. There was a higher abundance of eggs on the control (Citrus macrophylla Wester) than nearly all accessions of P. trifoliata, and zero eggs were laid on 36% of the accessions. Additionally, more eggs were laid on the control than 10 of 34 accessions of xCitroncirus. Lifespan of adults was ~2.5-5 times longer on 11 of the 17 trifoliates and trifoliate hybrids we tested. P. trifoliata appears to have antixenosis and antibiosis resistance to ACP, but we must next identify the traits that promote resistance. To identify chemical mechanisms that may promote resistance, we collected volatiles from several pairs of closely related susceptible/resistant accessions of trifoliates and trifoliate hybrids and found differences in the volatile profiles.