Main viruses in sweet cherry plantations of Central-Western Spain

Sweet cherry trees (Prunus avium L.) are susceptible to a range of diseases, but there have been no studies to date about the viral infection of sweet cherry trees in Spain. To determine the phytosanitary status of Spanish sweet cherry plantations, the incidence and leaf symptoms induced by Prune dwarf (PDV), Prunus necrotic ringspot (PNRSV) and Apple chlorotic leaf spot (ACLSV) viruses were investigated during 2009. Young leaf samples were taken from 350 sweet cherry trees, corresponding to 17 cultivars, and were analysed by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). To associate the leaf symptoms with the virus, 50 mature leaves from each infected tree were visually inspected during the summer. The ELISA results revealed that 72 % of sweet cherry trees were infected by at least one of the viruses. PDV occurred in all sampled cultivars and presented the highest infection rate, followed by ACLSV and PNRSV. A high number of trees showed asymptomatic, in both single and mixed infections. The leaf symptoms associated with the viruses involved generalized chlorosis around the midvein (PDV), chlorotic and dark brown necrotic ringspots on both secondary veins and intervein regions (PNRSV), chlorotic and reddish necrotic ringspots (ACLSV) and generalized interveinal chlorosis (PDV-PNRSV)

Characterization and long-term performance of the Radon Trapping Facility operating at the Modane Underground Laboratory

International audienceRadon is one of the main potential sources of background radiation for any rare event experiments like neutrinoless double beta decay or dark matter experiments. The Radon Trapping Facility (RTF) installed in 2004 at the Modane Underground Laboratory (LSM) has been running for nine years providing radon-purified air at a level of 10 mBq m−3 for several experiments. The radon suppression principle is based on a radon physical adsorption using cooled compressed air at −55 °C pumped through a column filled with the K48 activated charcoal. After disassembling of the RTF, the 2.6 m high charcoal column has been divided into several layers in order to study with different techniques the dynamic adsorption coefficient (the K-factor) as a function of the depth and the radon spatial trapping profile by measuring the 210Pb activity. It has been demonstrated that after almost a decade of running, the K-factor of the activated charcoal remains constant except for the first few cm of the column. Furthermore, it has been demonstrated that the mass activity of 210Pb as a function of the depth of the charcoal column exhibits an exponential decay profile. The radon mean retention time τ R of (47.6 ± 1.2) days and the radon mean free path of (28.9 ± 0.4) cm have been derived and found to be consistent at 1σ with the ones obtained from the K-factor study, i.e. from a total independent measurement. The radon suppression factor of the RTF of has been also estimated with a value consistent at 2σ with the suppression factor measured during the RTF operation. Thus, this study has proven the capacity of the RTF to purify the LSM air from radon by more than three orders of magnitude during nine years of operation