HLB in Argentina: a New Disease Outbreak

Huanglongbing (HLB) caused by Candidatus Liberibacter asiaticus was reported in 2004 in São Paulo, Brazil and three years later in the southern state of Paraná, 300 km away from Argentina’s Northeastern border. In 2009 the Argentine citrus industry (AFINOA and CECNEA) and the institutions MAGyP, SENASA, INTA, INASE, and Obispo Colombres set up a task force to develop quarantine guidelines for prevention of introduction of HLB into Argentine citrus areas. This program is based on measures including 1) border inspections, 2) citrus nursery certification, 3) control on the production, transit and trade of citrus fruit, 4) field survey and diagnosis for the early detection of the disease in trees or the vector Diaphorina citri in citrus groves, 5) development of research and technology capacity, and 6) communication about the quarantine program and the disease. Diagnostic laboratories were set up in each citrus region and more than 100 inspectors were deployed in different citrus areas for 1) survey of Diaphorina citri by yellow sticky traps, 2) visual inspection of Murraya paniculata, 3) inspection of all citrus nursery production under aphid mesh screen according to Resolution 930/09, and 4) survey of 100 % of the citrus area (150,000 ha)  with at least 10 surveys of the highest risk area; There are 52,000 inspection locations for 13,160 tree or Diaphorina samples.  In June 2012, a positive detection of HLB was confirmed in a backyard tree in the Northern Misiones Province across the border from Brazil. Since then, 5 surveys were carried out in the area surrounding the focus with the detection of 15 positive trees, all in backyards.  The HLB positive trees include 12 tangerines, and 3 Rangpur limes from 7 to more than 10 years old.  In all cases, the trees were eradicated by the owner.  The psyllid population in this area is very low and all PCR samples of the vector are negative.  At present, HLB has not been detected in commercial groves