Experiences of Rain-fed Tomato Production in an Open Field

Tomatoes in Ethiopia are conventionally grown in an open field during dry periods using irrigation. Rain fed tomato production in an open field was considered difficult mainly because of disease attack leading to complete destruction of tomato plants since rain contact with the foliage favors development and spread of diseases. Seasonality of production and fluctuations in the supply of fresh tomatoes leading to market glut during in season and shortage during off season was also reported in many countries including Ethiopia, Kenya, Nigeria, Nepal and India. Rain fed tomato production in an open field is however successfully demonstrated with the use of appropriate integrated disease management (IDM) practices. Multiple strategies of using cultural, physical, mechanical, biological and chemical options help to limit development and spread of diseases. Control measures include the use of resistant varieties, seeds free from pathogens, seed treatment, improved drainage, proper sanitation, keeping cultivated fields clean and free from weeds and other foreign material that can serve as host for the pathogens. Appropriate field bed preparation, spacing, fertilization and destroying infected plants and throwing them away from the field are also vital. Site selection is an important initial step for IDM where well drained soil is preferred. Tomatoes benefit from crop rotation. Growing tomato in a field planted the previous season with tomato, pepper, eggplant, or other solanaceous crop should be avoided. Ridging and staking are also crucial specifically to drain excess water and to avoid foliage and fruit contact with the soil, respectively. It may also be critical to apply preventive and curative fungicides. Spraying fungicides namely, Agrolaxyl (3 kg/ha) and Ridomil Gold Mz 68 WG (3kg/ha), interchangeably at seven to ten days interval depending on the weather condition and disease incidence were found effective in mitigating the development of foliar fungal diseases at Woreta in Ethiopia. Scouting to monitor for plant disease symptoms and analysis of every hour weather conditions should be seriously considered, otherwise, tomato plants that appear healthy this morning or evening would be completely lost the other morning or evening for diseases such as late blight spreads very fast wiping away plants within a short time.