Concurrent Session 2E
Risk Assessment, Economic Analysis, and Extension Education for Asian Citrus Psyllid and Huanglongbing Disease Management in California
Beth Grafton-Cardwell, UC ANR Cooperative Extension Specialist, Dept. of Entomology, UC Riverside
One of the most potentially devastating pests to arrive in California in recent times is the Asian citrus psyllid (Diaphorina citri; ACP). ACP was first detected in southern California in 2008 and spread throughout that region over a 4-5 year period. It is now found in low densities in the Central Valley and as far north as Santa Clara and San Joaquin Counties. This pest readily feeds on and damages the leaves of citrus and close relatives in the Rutaceae family. ACP is a danger to citrus because it is an efficient vector of the bacterial pathogen Candidatus Liberibacter asiaticus (CLas) that causes the incurable citrus disease huanglongbing (HLB). This disease produces progressive mottling of leaves, deformed and off-flavor fruit, plant stunting, and eventual plant death. There is no cure for HLB and control is limited to psyllid management and infected-tree removal. A single CLas infected tree was found and removed in Los Angeles County in 2012. It is likely that there are more infected trees in southern California, however the 1-2 latent period before symptoms makes finding the trees difficult. In addition, the disease is rapidly spreading northward in Mexico and will reach California soon. California citrus is a $2 billion dollar industry and 60% of residences have at least one citrus tree. HLB has the potential to decimate the commercial citrus industry and change the landscape of residential California. The Citrus Pest and Disease Prevention Program (CPDPP), funded by citrus growers, is conducting a statewide ACP/HLB detection and management program. Our UC ANR funded project complements their efforts by providing an easy-to-use web-based interface for citrus industry members and homeowners that provides maps of citrus, the current distribution of the pest and disease, parasite releases and quarantine boundaries (http://ucanr.edu/sites/ACP). The site also provides information on how to detect and manage the psyllid and the disease and provides estimates of the cost of management for growers and homeowners. Additionally, the team is developing economic analyses of the cost of eradication (two pesticide treatments) and areawide management (cost of season-long treatments and tree replacement). We are conducting outreach programs to extend the results of these analyses to stakeholders throughout California. This project is assisting citrus growers, policymakers, and homeowners with ACP/HLB management decisions.