Surveys of virus diseases and molecular identification of viruses affecting pepper crops (Capsicum spp.) in southern Benin

Boosting the production of market garden products is a top priority for agricultural development in Benin. Chili pepper (Capsicum spp.), an economically important spice, is widely cultivated for its fruits in different parts of the country. Viral diseases are known to have a devastating impact on production. The objective of this study was to identify the viruses associated with pepper cultivation in southern Benin. Surveys and sample collections were conducted in five districts (Ouidah, Kpomassè, Sèmè, Cotonou, and Abomey-Calavi) from three departments (Atlantic, Littoral, and Ouémè) in September 2021. Disease incidence and severity of infection were assessed. Leaf samples from symptomatic and asymptomatic plants were collected randomly from farmers’ fields and were analyzed for viruses by RT-PCR using twelve primer pairs for different viruses sought. The overall high incidence of diseases varied according to the localities between 84.76% and 100% with an average of 94.46%. As for the severity of the disease, it varied significantly depending on the location of 3.24 (in Sèmè-Kpodji) to 2.56 (in Ouidah Cotonou) on average. The analysis of the data obtained by the detection of the presence of viruses in the various samples by RT-PCR shows the following occurrences: potato virus X (PVX) 77.36%, potato virus Y veinal necrosis strain (PVYn) 52.83%, cucumber mosaic virus (CMV) 47.17%, pepper vein virus (PeVYV) 32.08%, potato yellow mosaic virus (PYMV) 32.08%, Polerovirus 32.08%, Begomovirus 32.08%, tomato spoon yellow leaf (TYLCV) 18.87%, tomato spotted wilt virus (TSWV) 15.09%, pepper mottle virus (PepMoV) 11.32%, pepper mild mottle virus (PMMoV) 03.77%, and PVY 0.00% in the five districts surveyed during the periods under survey. Of the twelve groups of viruses searched for in the samples, eleven were found. Each of the samples is infected with one to seven of the twelve viruses sought. Mixed infections were common in most samples, and the high incidence suggests that the cultivars are highly susceptible to viral infections.