LIBRO-CONGRESO-CITRUS

S12P39
Unforbidden fruits: Preventing citrus smuggling by introducing varieties culturally significant to
ethnic communities
Karp D. 1 , Siebert T. 1 , Vidalakis G. 2 , Krueger R.R. 3 , Lee R.F. 3 , and Kahn T. 1
1University of California, Riverside, Department of Botany and Plant Sciences, United States; 2University of California, Riverside,
Department of Plant Pathology and Microbiology, United States; and 3United States Department of Agriculture, National Clonal
Germplasm Repository for Citrus and Dates, United States. dkarp@ucr.edu
Fruits and vegetative materials of citrus and citrus relatives are commonly smuggled into California,
presenting a risk of introducing Huanglongbing (“Candidatus Liberibacter” spp.) and its insect vector,
Asian Citrus Psyllid (Diaphorina citri), as well as other exotic citrus diseases and pests. Certain species and
cultivars such as curry leaf (Bergera koenigii), bael (Aegle marmelos) and Etrog citrons (Citrus medica)
are in demand from ethnic and religious communities, but supplies are limited because of quarantine
restrictions. Orchards, nursery trees, and disease-tested propagating materials necessary for their
production have not been available. The Unforbidden Fruits project aims to complement interdiction by
making pathogen-tested sources of these trees and leaves available in California. The project has collected
relevant germplasm, tested it for seed-transmissible diseases, and distributed seeds to California nurseries.
Before starting seed distribution, it was necessary to modify state and federal regulations that required
that all mother and increase plants in approved insect-resistant structures be derived from material that
has undergone shoot-tip grafting or therotherapy, which is impractical for citrus relatives such as curry
leaf and bael, for which no such protocols exist. Other citrus and citrus relatives of quarantine significance
include wampee (Clausena lansium), satkara (C. macroptera var. assamensis), and Asian cultivars of
pummelo (C. maxima).
S12P40
Introduction of control on main citrus diseases in P. R. China
Zhou C.Y.
Citrus Research Institute of Chinese Academy of Agricultural Sciences (CRIC), China. changyong@hotmail.com
Since 2001 ca. 100 modern virus-free citrus nurseries have been established in 13 provinces of China,
which have the capacity of producing ca. 114 million nursery trees per year. Through practicing the virusfree
propagation scheme, the losses caused by the graft-transmissible citrus diseases in inland area have
been dramatically reduced. Severe stem-pitting tristeza is still a threat to susceptible sweet oranges and
pummelos, a few mild isolates with potential protective capability screened from thousands of field isolates
have been being applied in field experiments for mild strain cross protection. In order to control quarantine
diseases and pests, Chongqing Citrus Quarantine Pest-free Zone has been being practically set up since
2007, as well as many efforts on setting up early warning system for citrus quarantine pathogens and
pests have been made in Chongqing. However, Huanglongbing (HLB) is still the main threat to the coastal
citrus areas, with high potential threat to those boundaries due to the northward movement of citrus
psyllids. In recent years, the control of HLB is forcefully organized by the plant protection stations of the
provincial governments. Three measures including strictly controlling the psyllid, removing diseased trees
promptly and planting HLB-free nursery trees are still recommended. Guangxi province is an example of
the successful control of HLB in the past few years, where the percentage of HLB has dropped down to now
less than 1% from over 10%, whereas much attention has not been paid in other coastal area. The control
of fungi diseases is focusing on Anthracnose, Brown Spot (Alternaria alternata), Black Spot (Phyllosticta
citricarpa) and Fruit Rot. This poster will also introduce the progress on virus-free scheme, construction
of quarantine pest-free zone, and a few state projects for public interest on controlling HLB, Citrus Canker,
virus diseases of fruit trees and fruit rot.
XII INTERNATIONAL CITRUS CONGRESS 2012 - 215
S12