Efficacy of Nitrification Inhibitors on Tomato Bacterial Canker and Wilt (Clavibacter Michiganensis Subsp. Michiganensis)

Abstract

Tomato bacterial canker and wilt is a destructive disease causing economic losses and affecting plant growth and yield. Due to the lack of disease resistant cultivars and non- effective chemicals, management of the disease is quite tricky. The aims of this study were (1) to identify Cmm strains isolated in different years using both classical and molecular tests, (2) to test the efficacy of ammonium sulphate fertilizers with nitrogenous inhibitors on Cmm disease development. Eight strains were identified as Cmm according to hypersensitive reaction on Mirabilis jalapa plant leaves, pathogenicity on tomato seeedlings and production of 614 bp on agarose gel electrophoresis. Non-nitrogenous classical ammonium sulphate as compare treatment, Dicyandiamide (DCD) and 3.5-Dimethylpyrazol glyceborate (DMPB) nitrification inhibitors included ammonium sulphate fertilizers were tested in pot experiments. Fertilizers were applied three times with one week intervals at the 100, 250 and 500 ppm doses as irrigation water and the efficacy of treatments compared with control plants. In two times repeated study, disease development inhibited from 42 to 78% and from 44 to 82% in the first and second trials, respectively. In both treatments, 500 ppm dose of all applied fertilizers was highly decreased the lesion development in plants. This study reported the effect of nitrification inhibitors on tomato bacterial canker and wilt for the first time. In conclusion, it would be beneficial to add inhibitor fertilizers to integrated control programs against tomato bacterial canker and wilt disease.