First report of Carnation necrotic fleck virus (CNFV) infecting carnations in India

In a survey of carnations grown in the Kangra valley of Himachal Pradesh, India, seventeen out of the thirty five varieties inspected showed mottling with grey streaks or red necrotic flecks. These symptoms were similar to those previously reported for Carnation necrotic fleck virus (CNFV) (Bar-Joseph et al., 1979). Sap from symptomatic leaves was inoculated on to Dianthus caryophyllus, D. chinensis and D. barbatus. Symptoms produced on these Dianthus spp indicators included mottling, vein clearing, flecking, gray streaks or red necrotic flecks. No symptoms were observed when Chenopodium spp were inoculated. Using a polyclonal DAS-ELISA kit (Agdia, USA), CNFV was detected in Dianthus indicator plants and the carnation varieties: Arthur Sim, Cabarett, Charmour, Dessio, Dusty Pink, Espana, Flair, Irma, Josh, LasPama, New Espana, Orange Triumph, Prinidello, Red Carso, Scania, Shocking Pink and White Candy. The virus was transmitted in a semi-persistent manner by aphid species Myzus persicae, Aphis craccivora and Aphis gossypii from D. caryophyllus to D. barbatus, with infection confirmed by DAS-ELISA. When examined by transmission electron microscopy, leaf dip preparations showed flexuous virus particles 1400 to 1500nm long. RT-PCR was conducted using degenerate primers specific to the closterovirus group (Karasev et al., 1994) and an amplicon of the expected size (~1000bp) was generated (Fig. 1). All these tests identified the virus as CNFV. CNFV has been reported from many countries, including the USA, France, Italy and Yugoslavia. This is the first report of CNFV infecting carnations in India.