Cassava Mosaic Disease and Associated Gemini Viruses in Bauchi State, Nigeria: Occurrence and Distribution

Abstract

Cassava mosaic disease is one of the most important biotic constraint affecting Cassava limiting the production potential of the crop in Northern Nigeria. This study was carried out to evaluate the current status of Cassava mosaic disease incidence, severity, infection type, whitefly abundance in the farmers’ field as well as to determine the virus strains causing the disease in Bauchi State, North eastern Nigeria. A total of thirty three (33) farmers’ fields were surveyed and in each field, thirty plants were assessed along the two diagonals with respect to disease incidence, severity, infection type and whitefly abundance and leaf samples were collected from each field for the virus diagnosis. The results revealed that Cassava mosaic disease incidence was highest in Ganjuwa (88.66%) and lowest in Darazo (43.33%). The disease symptom severity was generally mild. It was also highest in Ganjuwa (2.85) and lowest in Darazo (1.34). Whitefly infection is most prevalent (59.73%) than cutting borne infection (2.67%) in the Districts. Adult whitefly (<i>Bemisia tabaci</i>) population was highest in Ganjuwa (56.33) followed by Kirfi (40.93) and lowest in Toro (27.63). Polymerase chain reaction (PCR) results using specific primers for African Cassava mosaic virus (ACMV) and East African Cassava mosaic virus (EACMV) detected single infections of ACMV and EACMV in 62.4% and 12.9% of the positive samples respectively. Co-infections of ACMV and EACMV were detected in 10.6% of the tested samples. Continuous monitoring of Cassava Mosaic Viruses and whiteflies population is required to provide appropriate management strategies of the disease in Nigeria.