Onion (Allium cepa) is commonly known as “Queen of the kitchen” due to its high valued flavour, aroma and medicinal properties. Viruses are significant causal agents of plant diseases, leading to severe reduction in size and yields in onions. RNA viruses such as Tospoviruses, Allexiviruses Orthotospovirus and Carlaviruses affects global agriculture sustainability. Onion yellow dwarf virus (OYDV) is an important potyvirus that infect onions leading to 60% economic loss. A survey was initiated to determine the field disease incidence of OYDV using visual symptoms and serologically determine the occurrence of the virus using DAS-ELISA in four leading onion producing States in Nigeria. A total of 540 onion leaf samples were collected from 36 fields in 3 LGAs each of Kaduna, Kano, Zamfara and Kebbi. Assesses disease symptoms of irregular yellow stripping symptom was 29%, while chlorotic flattened leaves with downward curling was 16.3% on sampled onion plants. Kebbi state had the highest cumulative symptom incidence of 39.3% on infected onion fields, followed by Zamfara (35.86%) which was at par with kano (35.23) and the least was Kaduna (25.31%). Among the 12 LGAs surveyed, Jega LGA had the highest observed disease incidence of 13% followed by Shinkafi 11% whereas Sabon Gari had the least value 7%. DAS-ELISA, showed the presence of OYDV in Zamfara with 4% and Kebbi 7% disease incidence respectively. However, the virus is absent, Kaduna and Kano, as such it is safe to conclude that the symptoms noticed could be said to be those of other disease(s) that show varying degree of similarities or due to other factors. OYDV could be threatening if not managed appropriately. Farmers need to be enlightened on this disease and management strategies such as pest control and other measures to ensure the disease remains below the threshold level avoid higher level of occurrence.

DAS-ELISA, Onions, OYDV, RNA virus, Serological detection.

biology

Presentation: oral presentation