15. SEVERE ISOLATES CAUSING GRAPEFRUIT STEM PITTING

15. SEVERE ISOLATES CAUSING GRAPEFRUIT STEM PITTING

82
XVIII Conference of the IOCV
15. SEVERE ISOLATES CAUSING GRAPEFRUIT STEM PITTING ARE LOCATED IN
CHILEAN PICA OASIS
Ximena A. Besoain1,2, Edson Bertolini1, Fiona Ramella2, María Teresa Gorris1, Margarita
Torres2, Mariano Cambra1
Instituto Valenciano de Investigaciones Agrarias, Apdo. Oficial, 46113, Moncada, Valencia,
Spain;
2
Facultad de Agronomía, Pontificia Universidad Católica de Valparaíso, Casilla 4-D, Quillota,
Chile.
1
Citrus tristeza virus (CTV) was previously reported in Chile affecting Meyer lemon in the
1960’s decade, but no field symptoms were observed. Considering the importance of tristeza
disease, a broad survey was conducted sampling 1% of trees present in the main commercial
citrus orchards, and CTV was serologically detected. One hundred CTV isolates obtained from
different hosts and zones were biologically, serologically and molecularly characterized. CTV
was detected in almost all the citrus regions of Chile associated to all citrus species, with a media
of 0.38%. Decline symptoms (DI) were not found on trees grafted on sour orange. In Pica Oasis,
stem pitting (SP) was found affecting grapefruit and Mexican lime trees. Most isolates present
in the central zone were considered mild (MCA 13 negative), while in the north presence of
severe isolates was established, some capable of causing SP on grapefruit and sweet orange on
greenhouse experiments, all MCA13 positive and molecularly associated to the VT type isolate.
Citrus Research & Technology, Cordeirópolis, v.31, Suplemento, p.1-129, 2010