Limestone rate affects potato bacterial wilt disease and <i>Ralstonia solanacearum</i>’s population in the soil in the Western Highlands zone of Cameroon

Abstract

Potato bacterial wilt (BW) caused by Ralstonia solanacearum, is one of the major constraints to potato production in Cameroon. In order to reduce yield losses due to BW, this study aimed at investigating the effect of limestone on bacterial wilt disease, and on the R. solanacearum’s population in the soil. Potato tubers were grown in pots in a screen house of the University of Dschang, from February to May 2021. The experimental design was a split plot design made up of three replicates of two potato genotypes (Dosa and Jacob2005), 05 limestone rates (14.7 g, 29 g, 44,1 g, 58.8 g and 73.5 g per plant) and 2 controls (no liming without inoculation and no liming with pathogen inoculation). Plants were inoculated with 25 ml of bacterial suspension, containing 10⁸ CFU/ml. The bacterial population in the soil was assessed by counting colonies under microscope. Data were collected on BW incidence, bacterial population in the soil, soil pH, yield components and latent infection. The results showed that low BW incidence was associated with high rate of limestone in both genotypes. Limestone rate increased soil pH while reducing the pathogen population in the soil. The higher tuber weight/plant was obtained with limestone rate ≥58.8 g/plant. Liming enabled to avoid latent infection during storage. Thus, soil amendment with limestone at 58.8 g/plant can reduce R. solanacearum population in the soil and lower the impact of bacterial in the field as well as in the store in Dschang locality.