OCCURRENCE, DISTRIBUTION AND ALTERNATIVE HOSTS OF CASSAVA VIRUSES IN KANO AND KATSINA STATES, NIGERIA

OCCURRENCE, DISTRIBUTION AND ALTERNATIVE HOSTS OF CASSAVA VIRUSES IN KANO AND KATSINA STATES, NIGERIA

Abstract:

Cassava mosaic virus is said to occur in all growing areas in Africa and a substantive land area is devoted to cassava in Kano and Katsina State of Nigeria. There is also the need to investigate if Cassava congo sequivirus recently reported in Kaduna and Sokoto States occurs in the States. Field surveys were conducted during the 2016 dry and wet seasons in three local government areas each of Kano and Katsina States of Nigeria to determine the occurrence, distribution and alternative hosts of viruses of cassava (Manihot esculenta Crantz). A total of 18 cassava farms were surveyed in the twoStates (nine in each State). Sampling was done in 5 x 5 m2 quadrats in each field of the three selected fields per Local Government Area. Cassava plants with mosaic, distortion, stunting, chlorosis and necrotic symptoms on leaves, as well as, those with no obvious virus disease symptoms were sampled. A total of twenty weed samples, were also collected during both dry and wet seasons andanalysis was carried out for the presence of cassava viruses. Double Antibody Sandwich Enzyme-Linked Immunosorbent Assay (DAS-ELISA) was used to detect Cassava congo sequivirus(CCSV) while the Triple Antibody Sandwich Enzyme Linked Immunosorbent Assay (TAS-ELISA) was used to detect African cassava mosaic virus(ACMV) and East african cassava mosaic virus (EACMV). After the analyses, three Cassava viruses Cassava congo sequivirus, African cassava mosaic virusand East african cassava mosaic virus were detected either singly (ACMV 30.4 %, EACMV 21.5 %, CCSV 17.8 %) (ACMV 28.9 %, EACMV 25.2 %, CCSV 28.1 %) or in mixed infections of two or even the three viruses (ACMV + EACMV 11.1 %, ACMV + CCSV 2.2 %, EACMV + CCSV 1.5 % and ACMV + EACMV + CCSV 1.5 %) (ACMV + EACMV 9.6 %, ACMV + CCSV 14.8 %, EACMV + CCSV 5.9 % and ACMV + EACMV + CCSV 3.0 %) in all the Local Governments Areas of Kano and KatsinaStates respectively. This provides the first report of these viruses in the States and the second report of the occurrence of CCSV in Nigeria. None of the weeds could be confirmed as hosts of the viruses.

OCCURRENCE, DISTRIBUTION AND ALTERNATIVE HOSTS OF CASSAVA VIRUSES IN KANO AND KATSINA STATES, NIGERIA