OCCURRENCE, DISTRIBUTION AND ALTERNATIVE HOSTS OF JATROPHA MOSAIC VIRUS IN SOME NORTHWESTERN STATES OF NIGERIA

ABSTRACT
Field survey was conducted in 2015 between August and September in three Local Government Areas of Kaduna, Katsina and Kano States of Nigeria to determine the incidence, distribution and alternative hosts of Jatropha Mosaic Virus on Physic nut (Jatropha curcas L). A total of twenty seven (27) Jatropha curcas farms were surveyed in three States (Kaduna, Katsina and Kano), nine in each State. Sampling was done in three demarcated 12 × 12 m² plot in each of the selected fields per Local Government Area. Jatropha curcas and other plant species showing virus like symptoms which included mosaic, leaf curl, mottling, stunting, chlorosis, yellowing, and necrotic symptoms as well as asymptomatic plants were sampled. A total of twenty eight weed samples were randomly collected from the three States. Analysis was carried out for the detection of viral components (DNA-A and B) and sub-viral components (DNA-β and 1) of Jatropha mosaic virus by Polymerase Chain Reaction (PCR). Jatropha mosaic virus disease was present in all farm locations and the incidences recorded. The highest disease incidence in Katsina State (95 %) was recorded at Walin-Hausa Foundation farm (Tsanni) in Batagarawa LGA, and the lowest (43.75%) in Katarda of Batagarawa LGA. In Kaduna State, the National Research Institute for Chemical Technology (NARICT) Jatropha curcas field had the highest incidence (83.61%), with the lowest (42.86%) at Gwaraji in Igabi LGA. The highest disease incidence (88%) recorded in Kano State was at Marmara in Tudun-Wada LGA, and lowest (2%) in the Institute for Agricultural Research (I.A.R) sub-station Jatropha curcas farm at Minjibir LGA. The viral components DNA-A and B were not detected in all the fields across the three States, as well as the sub-viral component DNA-1 while the sub-viral component DNA-β was detected only on some samples from NARICT and I.A.R Jatropha
curcas fields both in Sabon-Gari Local Government Area of Kaduna State. The helper virus component (DNA-A) was not detected. None of the plant species samples tested positive to any of the viral and sub-viral components of interest in this study from the three States. This is the first report of a satellite virus DNA-β of JMV in Kaduna State of Nigeria. In view of the importance of Jatropha curcas L. in Nigeria, threats such as Jatropha mosaic virus attack to its production should be considered seriously and prevention as well as management strategies be pursued vigorously.