Screening Citrus Germplasm for Resistance to Huanglongbing Disease: Inoculation Procedures

The Asian citrus psyllid (ACP), Diaphorina citri, is an important pest because it vectors bacteria responsible for a serious disease of citrus known as huanglongbing (citrus greening disease). USDA-ARS researchers recently established a program for screening citrus germplasm for resistance to the disease bacterium.  The first step of the program is to inoculate germplasm.  Planting germplasm in an orchard with high levels of inoculum and encouraging infestations of ACP was considered too slow of an approach.  Although citrus can be manually inoculated by grafting trees with infected budwood, we preferred using infected ACP because this is what occurs in nature and also because traits conferring resistance to the vector might contribute to disease resistance.  This presentation will review our inoculation procedures.