Controle da murcha bacteriana do tomateiro com a incorporação de guandu e crotalária ao solo e com enxertia em porta-enxerto resistente

Abstract

The bacterial wilt caused by Ralstonia solanacearum is a limiting factor to the tomato crop in the Recôncavo region of the State of Bahia, Brazil. This work aimed to evaluate the tomato bacterial wilt control, using different sources and concentrations of organic matter and grafting varieties to a resistant rootstock, as well as evaluating the growth and yield of the grafted plants. Two commercially available organic composts and the aerial fresh parts of pigeon peas (Cajanus cajan) and crotalaria (Crotalaria juncea), in the concentrations of 10, 20, and 30% (v/v) were tested by incorporating to a soil infested with R. solanacearum. The soil with pigeon pea or crotalaria was incubated for 30 and 60 days, before planting. Tomato seedlings cv. Santa Clara were transplanted to the substrates, and symptoms of bacterial wilt were evaluated. For grafting experiments, local tomato genotypes and the hybrid Hawaii 7996, were evaluated for resistance to R. solanacearum. The hybrid Hawaii 7996 was used as rootstock, and cv. Santa Clara, Santa Cruz Kada, and Débora Plus were used as the scion parts. The soil incorporation of pigeon pea and crotalaria, for all concentrations, controlled 100 % bacterial wilt for treatments with 30 days of incubation. However, the concentration of 10%, with 60 days of incubation, did not control the disease at all. Only the hybrid Hawaii 7996 can be recommended as a resistant rootstock to R. solanacearum, allowing 100 % control of bacterial wilt. The total productivity and average fruit weight did not differ among grafted treatments and non-grafted tomato seedlings. These results imply that the incorporation of aerial parts of pigeon peas and crotalaria to soil and grafting to the hybrid Hawaii 7996 as rootstock can be considered as alternative methods for the control of bacterial wilt.