FIELD SURVEY OF CASSAVA MOSAIC DISEASE AND ITS WHITEFLY (Bemisia tabaci Genn.) VECTOR IN KEBBI AND KATSINA STATES, NIGERIA

Abstract

Demand for cassava roots and its products by man and industries is rising in Nigeria. However, cassava mosaic disease (CMD) is threatening cassava production in the country. This research was conducted to assess the current status of CMD and its whitefly-vector in Kebbi and Katsina States, Nigeria, during the 2015, 2017 and 2020 growing seasons. Cassava fields were sampled along the major roads at distance of 10 km apart, 30 cassava plants were randomly assessed per field for CMD status and whitefly abundance. Symptomatic and asymptomatic cassava leaf samples were collected from the surveyed fields and indexed against African cassava mosaic virus (ACMV), East African cassava mosaic virus(EACMV) and East African cassava mosaic Cameroon virus (EACMCV) using polymerase chain reaction. Significant (P = 0.05) differences were obtained for CMD incidence for both years and states. Overall, Kebbi State had high CMD incidence (2015: 84.63%, 2017:81.11%, and 2020:21.57%). Disease severity was statistically similar in both year and states. Whitefly abundance significantly increased in 2017 and 2020 compared to 2015 (Kebbi 2015:5, 2017:11, 2020:16) (Katsina 2015:8, 2017:13, 2020:12) per leaf. Overall, ACMV (2015: 92.00%, 2017: 73.00%, and 2020:46.00%) was detected in more samples than EACMV (2015:29.00%, 2017:21.00%, 2020:13.00%) and EACMCV (2015:5.00%, 2017:13.00%, and 2020:7.00%) in Katsina State and it had the highest incidence of ACMV than Kebbi State. EACMV also occurred as mixed infection with ACMV. The findings of this research provide the current status of CMD and its vector in the study areas and that ACMV, EACMVand EACMCVincidences are increasing in states.