Management of bacterial wilt of tomato using resistant rootstocks

Bacterial wilt (Ralstonia solanacearum) is a devastating disease of tomato that is quickly spreading and affecting many fields causing a reduction in yield and income to farmers. The objective of the study was to determine the effect of using tolerant tomato rootstock in wilt management. Field experiments were carried out in Kiambu, Ruiru, Karen and Isinya sites in farmers’ greenhouses where previous crops were affected by the disease. A greenhouse variety Anna F1 was used as a scion and was grafted on rootstock varieties Cheong gang, Shin cheong gang and on a local wild tomato variety. Efficacy of biological product Rootgard® and a copper fungicide Nordox® were tested while non-grafted Anna F1 used as a control. Results strongly indicate that bacterial wilt disease severity and incidence was reduced when the susceptible Anna variety was grafted on Shin cheong gang. Grafting susceptible Anna F1 tomato variety on bacterial wilt tolerant Cheong gang variety reduced bacterial wilt incidence by 92%, Shin cheong gang by 95% and by 64% with the wild tomato variety. Plants grafted onto Cheong gang and Shin cheong gang had lowest disease incidence and produced high yield of tomato in quantity and quality when compared to non-grafted Anna F1. The study indicated that bacterial wilt can be effectively managed by grafting susceptible varieties on tolerant rootstocks. The grafted plants can be planted in fields that are infected with R. solanacearum.