LIBRO-CONGRESO-CITRUS

S12P01
Yield loss modeling of “Candidatus Liberibacter asiaticus” on Persian lime (Citrus latifolia) in
southern Mexico
Flores Sanchez J.L. 1 , Mora Aguilera G. 1 , Loeza Kuk E. 2 , Domínguez Monge S. 1 , Acevedo Sánchez G. 3 , and López Arroyo J.I. 4
1 Colegio de Postgraduados (Colpos), Fitopatología, México; 2 INIFAP-Campo Experimental Mocochá, Yucatán (INIFAP), Fitopatología,
México; 3 Laboratorio de Análisis Epidemiológico de Plagas Reglamentadas (SINAVEF Lab), Fitopatología, Colpos, México; 4 INIFAP
-Campo Experimental General Terán, Nuevo León (INIFAP), Entomología, México. flores.jorge@colpos.mx
In Mexico, Huanglongbing caused by Candidatus Liberibacter asiaticus (Las) was detected in Yucatan in 2009
mainly on Citrus latifolia and C. aurantifolia. An early infected Persian lime orchard was selected to estimate
the yield loss caused by Las for purpose of decision making on disease management. A restricted random
block design with paired healthy and diseased trees, verified by real time PCR, was established to assess
eight morphologic and organoleptic fruit variables in 2011. Weight, size, peel thickness, juice volume and pH
were statistically higher on healthy trees (T1) and asymptomatic branches (T3) of positive trees with regard to
symptomatic branches (T2) (Tukey, p= 0.05). Differences were not found between T1 and T2 with exception
of fruit size. Brix and titratable acidity were not different on any treatment. Las induced higher detrimental
effect on weight (17.3%) and juice volume (18.6%) being dependent on disease severity (x) (0=healthy, 1=25,
2=50, 3=75, 4=100% canopy symptoms): Yweight = 217.2-4.2x 0.03x 2 , R 2 = 0.86; Yvolume = 645.4-11.7x 0.09x 2 ,
R 2 = 0.82. Yield detrimental effect was associated with bacterial concentration base on its relationship with
severity: Y[bacteria] = 1.174 0.8x-0.0067x 2 , R 2 = 0.91. HLB-Per 1.0, a MS Excel program, was developed to
estimate the impact on production and profit considering different Las infection periods. The model was also
validated with C. aurantifolia. This is the first yield loss report on Persian lime.
S12P02
Seasonal detection of Huanglongbing symptomatic trees and Diaphorina citri in citrus groves in
Sao Paulo State, Brazil
Bassanezi R.B.
Fundo de Defesa da Citricultura (Fundecitrus), Departamento Científico, Brazil. rbbassanezi@fundecitrus.com.br
Citrus Huanglongbing (HLB) was first reported in Sao Paulo State (SPS), Brazil, in 2004 and since that the
management of this disease has been based on detection and elimination of symptomatic trees and monitoring
and control of the insect vector Asian Citrus Psyllid (ACP), Diaphorina citri. To maximize the labor and financial
resources for best HLB management it is important to determine the periods when HLB-symptomatic trees and
ACP are detected by scouting teams in the field. To analyze the seasonality of HLB-symptomatic trees detection,
data of monthly scouting of 100% of citrus trees in all citrus blocks of 24 citrus groves in 20 municipalities of
Southern, Southwestern, Eastern and Center regions of SPS, from 2005 to 2011, were used. For ACP, data of
fortnightly assessments of yellow stick traps placed in four groves without insecticide application in Eastern
and Center regions of SPS, from 2005 to 2011, were used. Although HLB-symptomatic trees were detected in
all months, 79% of total amount of detected diseased trees was found from February to August and less than
10% from October to December. ACP was also detected in all months, but there were two picks of detection in
October and December, corresponding to spring and summer main citrus vegetation. More than 80% of ACP
was detected from August to January. Due to the simultaneous presence of considerable amount of ACP and
symptomatic trees in August and January, these months could be key periods for HLB management.
S12P03
Identification of ”Candidatus Liberibacter” and phytoplasma and evaluation of their association
with citrus Huanglongbing in China
Su H.N., Wang X.F., Tang K.Z., Li Z.A., and Zhou C.Y.
National Engineering Research Center for Citrus, Citrus Research Institute, Southwest University, College of Plant Protection, China.
huanansu211@163.com
Citrus Huanglongbing (HLB) is one of the most devastating citrus diseases worldwide. Prior to 2004,
“Candidatus Liberibacter” spp. was considered as the putative causal agents of HLB, though Koch’s postulates
XII INTERNATIONAL CITRUS CONGRESS 2012 - 199
S12