Differential development of wilt and stem rot diseases in grafted bell pepper (Capsicum annuum, L.)

In bell pepper production, diseases caused by soil-borne pathogens are a serious problem. The use of chemicals remains the main method for the control of soil-borne pathogens, with poor results in many cases. However, grafting has been proposed as an alternative which can also improve control. The present study analyses and compares the development of diseases caused by soil-borne pathogens in grafted and non-grafted sweet bell pepper plants. Plots of cultivars Fascinato and Janette non-grafted and grafted on Terrano rootstock were established on a farm managed under the shaded greenhouse system. Phytophthora capsici and Rhizoctonia solani AG4 were identified causing wilt. Fusarium solani was identified causing stem rot. Terrano resisted wilt by reducing the apparent infection rate and the final incidence in the Fascinato variety by 92% and 89%, respectively, and in the Janette variety by 99% and 98%, respectively. However, Terrano was not resistant to stem rot. Compared to non-grafted plants, Terrano had a higher apparent infection rate and final incidence, which in Fascinato were 56% and 60%, respectively, and in Janette were 97% and 99%, respectively. Terrano also affected the spatial patterns of both wilt and stem rot. These results show that it is necessary to supplement the use of Terrano with other strategies. This complicates the goal of reducing the use of chemicals, environmental pollution and the costs of control in the production of sweet bell pepper.