Management of Early Blight Diseases Caused by Alternaria Alternata in Tomato Plants (Lycopersicon esculentum) in White Nile State season (2017-2018)

Résumé

To manage the disease, the study involved the investigation of the effect of different concentrations of natural products formulations and fungicide, Seed Star 42, on the incidence of the disease under natural infection conditions for two successive seasons. Three concentrations were tested from each of the natural products e.g. Neem oil, aqueous extracts of plants leaves of argel, Neem and usher plus mesquite plant fruits extract, as follow; 2.5, 5 and 10 ml/l and 25, 50 and 100% for each of the extracts respectively. This in addition to argel 5gm powder per hole and the fungicide seed star 42 at the rate of 5 gm/Kg seeds as seed dressing plus the control. The assessment of the treatments effects on the pathogen was recorded as percentage disease incidence. The result showed an invariably high effect on disease incidence obtained by the concentrations of Neem oil at 5ml/l, argel at 5gm/hole and seed star 42 at 5 gm/Kg seeds which gave almost 100% disease control where the percent was 0.0, 0.0, 1.0 at the forth count respectively compared to control which was 16.33. It is noteworthy that those  Journal Of Afro-Asian Studies ------- The seventeenth issue of May 2023 -------  Democratic Arab Center For Strategic, Political & Economic Studies Berlin / Germany 188 encouraging results were confirmed by the same experiment repeated the season after. However, the effect of Neem leaves extracts at the three concentrations, 25, 50 and 100% was the lowest in disease control, at the forth counts; 8.67, 9.67 and 10.33% respectively, compared to the other treatments and this was an indication of inefficacy. Beneficial effects expressed as reduction in percent of fruits infected were also recorded due to application of these three treatments. Apparently, there was also obtained a high yield gains in this study upon treatments of tomato with those three products. The yield was almost doubled by application of the forgoing products giving a total of 41.6, 46.0 and 36.0 Kg per treatment respectively compared to control 23.1 Kg. The current results were considered promising and encouraging to carry out a photochemical analysis of Argel plant using different solvents so as to determine the bioactive ingredient in the plant. Obviously, the present study is presenting for the first in Sudan the highly effective method for control of early blight disease in tomato using argel powder at planting time.