100 Chapman Hall
University of California, Riverside
Riverside, CA 92521

(951) 827-2246






.Research Positions.


Current extension education programs focus on the ecology and management of the following two invasive vectors of plant disease:

trap1. Glassy-winged sharpshooter & Pierce's disease management
The glassy-winged sharpshooter (Homalodisca vitripennis; GWSS) , a leafhopper that is native to the Southeastern US, has become a major pest in California over the last 15 years. Llike other native sharpshooters, direct feeding damage to plants is minimal. Rather the impact of this insect stems from its ability to transmit the plant pathogenic bacterium Xylella fastidiosa (Xf), which causes Pierce's disease in grapevines and a range of leaf scorch diseases in other plants. GWSS's invasion into California precipitated disease outbreaks in vineyards on an unusually large scale. Moreover, this insect and pathogen threaten other agricultural crops in the state. Management of Xylella diseases requires control of vector populations in source habitats (i.e. riparian corridors and citrus groves), disruption of sharpshooter immigration from source habitats, elimination of Xf reservoirs, and the development of plant varieties that are resistant to the pathogen. 

The following presentation provides a general overview of Xf biology and management (XF)

The following presentation describes ongoing research to develop effective sharpshooter control measures in vineyards (Grape Day)

Finally, the following blog has the most recent GWSS trapping data and other information for the Temecula Valley Areawide Control Program

hlb2. Asian citrus psyllid & Huanglongbing management in Southern California
The invasive Asian citrus psyllid (Diaphorina citri; ACP) a vector of the bacterium that causes Huanglongbing (HLB disease in citrus, has emerged as one of the primary threats to California agriculture. This pest readily feeds on citrus and close relatives, to which it can transmit the pathogens (Candidatus Liberibacter spp.) responsible for HLB or citrus greening disease. These diseases produce progressive mottling of leaves, deformed and off-flavor fruit, plant stunting, and eventual death. There is no cure for infected trees. ACP invaded California in 2008 and the first case of HLB was found in the Spring of 2012. Currently ACP is largely an urban problem in the state, with well over 97% of finds occurring in urban or suburban areas. Mitigating the potential impact of ACP and HLB hinges on the maintenance of regional quarantine zones and the development and widespread adoption of an integrated pest management program for residential, retail nursery, and commercial citrus.

The most recent map of ACP distribution in California can be found here.

General information on this new threat to California citrus can be found at the following site (CRB), or in the following presentation (BGC)

More detailed information on this insect and disease, including monitoring procedures and regionally distinct management recommendations can be found at the following site maintained by Dr. Beth Grafton-Cardwell: 


Department of Entomology
University of California, Riverside
Riverside, CA 92521