EVALUATION OF SEED PRIMING WITH SELECTED DISEASE CONTROL AGENTS FOR THE MANAGEMENT OF BACTERIAL WILT (RALSTONIA SOLANACEARUM ‘Smith’ Yabuuchi) OF TOMATO (SOLANUM LYCOPERSICUM (L.)

Abstract

Bacterial wilt, a soil and seed-borne pathogen have been implicated in yield loss of tomato with significant economic implications globally. Sole management options have not proved to be efficient as their efficacy are challenged by the pathogen genetic diversity, and the existence of a wide host range. Integration of management options targeted at prevention, rather than control, has proved to be more efficient than any single control method. The study aimed to develop a management option that is environment friendly, and cost effective through seed priming. Phytochemical (cold and hot extracts of garlic), and synthetic chemical (Metalaxyl + Copper (I) oxide (Red force®) and Mancozeb®) and antibiotics (Amoxicillin® and Ampicillin®) were evaluated at different concentrations for the management of Ralstonial solanacearum, in vitro using the agar well diffusion method. The most promising pathogen control agents were evaluated through seed priming at different intervals (24 and 48 hours) respectively on the seedling of the tomato plant. The in vivo study involved the evaluation of Ampicillin® (8mg/ml), Trichoderma harzianum (108cfu/ml), Red force® (6.67mg/ltr), cold garlic (40%) for 24hrs seed priming respectively. Red force® (6.67mg/ltr), Mancozeb® (6.67mg/ltr), hot garlic (30%), and Pseudomonas fluorescens (108cfu/ml) for 48 hrs seed priming respectively. The negative control (seed priming with sterile water and sown in an infested soil), and positive control (seed priming with sterile water and sown in an uninfected soil) were also evaluated. R. solanacearum was inoculated into the soil at 106 cell/ml for each of the most promising disease control agents. Results obtained showed that Red force® (6.67 mg/ltr) significantly reduced the bacterial growth compared to the other treatments, while T. harzianum recorded the highest seedling length at 24 hours and Mancozeb® (6.67 mg/ml) for 48 hours seed priming. P. fluorescens ((108cfu/ml)) significantly increase the number of fruits, fruit weight next to the positive control, and earliest number of days to flowering. T. harzianum (108cfu/ml), Red force® (6.67mg/ltr) at 24 hours, cold garlic extract (40%) hot garlic extract (30%), Red force® (6.67mg/ltr) at 48 hours, Mancozeb® (6.67mg/ltr) and Pseudomonas fluorescence (108cfu/ml) significantly reduced disease incidence and severity of the pathogen except for Aampicillin® (8mg/ml) while the number of leaves, plant height, and stem girth varies across the treatments. The result of this study signifies that seed priming is an effective management option against bacterial wilt disease of tomato.