Prevalence of sorghum diseases in Nigeria

A survey was conducted in farmers’ fields in Nigeria during the 1990 cropping season to determine the prevalence of sorghum diseases in the four major sorghum‐growing climatic zones (Sahel, Sudan, northern Guinea, and southern Guinea). The foliar diseases anthracnose (Colletotrichum graminicola) oval leaf spot (Ramulispora sorghicola) sooty stripe (Ramulispora sorghi) and grey leaf spot (Cercospora sorghi) were widely distributed. Anthracnose was predominant throughout the areas surveyed with ≥40% leaf area covered or destroyed by lesions in 70% of the surveyed fields. The incidence of other foliar diseases was low. Among the panicle diseases, long smut (Tolyposporium ehrenbergii) incidence was ≤10% in ≥20% farmers’ fields in the sahelian zone. Head (Sporisorium reilianum) covered (Sporisorium sorghi) and loose (Sphacelotheca cruenta) smuts were common, but their incidence varied from 1 to 10% in the Sahel, Sudan, northern Guinea and southern Guinea zones. Survey results based on ELISA indicated for the first time in Nigeria the presence of three virus diseases of sorghum: maize mosaic (maize mosaic virus), maize stripe (maize stripe virus), and a potyvirus in the Sudan, northern Guinea, and southern Guinea zones. Grain moulds, charcoal rot (Macrophomina phaseolina) and bacterial diseases were not observed during this survey

Hosts of Bemisia tabaci Genn. in Northern Nigeria

Intensive surveys conducted at Samaru and its environs in the northern Guinea Savanna of Nigeria between October 2000 and September 2002, indicated that Bemisia tabaci (Genn.) infests forty two (thirty three cultivated and seven wild) species of plants. Twenty nine of the plants were found in upland, two in the lowland and eleven in both upland and lowland (fadama) areas. Heavily infested plants were distorted, chlorotic and stunted. Symptoms of virus infection were associated with some of the infested plants. This is the first comprehensive report of hosts of B. tabaci in Nigeria

Analysis of Serological Variability and Hierarchical Distribution of Rice yellow mottle Sobemovirus Isolates in Northern Nigeria

ABSTRACT A panel of four monoclonal antibodies (MAbs) was used to study the immunological profile of Rice yellow mottle virus (RYMV) genus Sobemovirus. Serological profiles of 35 representative isolates of RYMV from Borno, Gombe, Kaduna, Kano, Niger, Sokoto and Zamfara states in Northern Nigeria. All the RYMV isolates were classified into three major serogroups (SG1, SG2 and SG3) and further separated into six subgroups (Sg1a, Sg1b, Sg2a, Sg2b, Sg3a and Sg3b). The results demonstrate a significant serological variability among RYMV isolates in Northern Nigeria. The hierarchical analysis of the serological profiles data revealed high viral load in Kano, Kaduna and Gombe states, these show they are suitable locations for strategic RYMV diagnostic and field epidemiological studies

Prevalence of Viruses Infecting Sorghum in Nigeria-A Review

Viruses infecting sorghum are widely distributed in Asia and Africa and are of economic importance. In recent years, apparent virus disease incidence has increased, probably due to changes in agricultural practices associated with the introduction of hybrids and new varieties that are being developed and released continuously. The first virus disease described on sorghum in the world was Sugarcane mosaic virus (SCMV). Nigeria is one of the leading sorghum producing countries in the world and most of its populace in the northern part depend on sorghum as their primary staple food and so far, seven viruses have been identified on sorghum in Nigeria: Maize mosaic virus (MMV), Maize stripe virus (MSpV), Maize streak virus (MSV), Sugarcane mosaic virus (SCMV), Guinea grass mosaic virus (GGMV), Sorghum mosaic virus (SrMV) and Maize dwarf mosaic virus (MDMV). This calls for proper molecular characterization and deployment of management strategies of the diseases the viruses incite. Future research needs are discussed