Citrus greening in commercial orchards in Puerto Rico
C. ESTEVEZ DE JENSEN (1), A. Vitoreli (2), F. Roman (3)
(1) University of Puerto Rico, Juana Diaz, U.S.A.; (2) Plant Disease Clinic/University of Florida, Gainesville, FL, U.S.A.; (3) University of Puerto Rico, Mayaguez, U.S.A.
Phytopathology 100:S34

Citrus greening (CG) associated with Candidatus Liberibacter asiaticus, was recently identified in Puerto Rico. Symptomatic and asymptomatic leaves of sweet oranges (cv. Valencia and Washington Navel), Lime (cv. Tahiti), grapefruit and mandarin were sampled in Castañer, Juana Diaz, Yahuecas and Isabela Municipalities. Standard Polymerase Chain Reaction (PCR) was performed on DNA extractions using primers OI1 and OI2. The 16S rDNA fragments with molecular weight of 1160 bp were amplified in an agarose gel at 1.5% and corresponded to the bacterium Candidatus Liberibacter asiaticus. Sequencing of the PCR products from Isabela confirmed amplification of Ca. L. asiaticus DNA. Sweet oranges and mandarins were severely affected at Isabela where tree decline was observed. In Castañer in a 600 acre orchard two out of 25 samples were positive for the disease. In a three year old Thaiti lime orchard in Juana Diaz, symptoms developed from mottled areas and yellowed shoots to stem and limb dieback within five months in 81 out of 352 trees. Ten samples out of 25 samples were positive for C. L. asiaticus. A survey of citrus greening and implementation of IPM practices to prevent the spreading of the disease are needed.