Abstract:
Fusarium wilt and Southern blight diseases are soil borne fungal pathogens of tomato that are known to cause yield losses in significant proportions. Sole management options employed to control these diseases have associated problems. The integration of disease management methods have proven to hold better advantage over sole reliance on any single control method. The study aimed to provide non-chemical management of Fusarium wilt and southern blight diseases of tomato. Trichoderma species (T. harzianum and T. viride) were evaluated for the management of Fusarium oxysporum f. sp. lycopersici (Schlecht) and Sclerotium rolfsii (Saccardo), causal agents of Fusarium wilt and Southern blight of tomato, separately, in vitro using the dual culture technique. The in-vivo study involved the evaluation of Trichoderma harzianum, the more promising from the in-vitro studies, and solarization against the pathogens. T.harzianum was evaluated at two concentrations of 107 spores/ml and 104 spores/ml. Two levels of solarization, one and two months, and the interactive effect between solarization and T.harzianum were also evaluated. Formaldehyde, a fumigant, was the standard check, while the control consisted of untreated soil. The pathogens were inoculated into the soil at 106 spores/ml for each. The test crop, the local tomato cultivar (oblong type) popularly called Hausa scissors, was purchased from the local market. The seeds were extracted, air-dried, and raised in the nursery on sterile nutrient-rich soil for 21 days. Tomato seedlings were transplanted in soil treated with Trichoderma and solarization. The soil was 15 kg contained in plastic pots of 15 liters. The plastic pots were placed in the open field throughout the growth period of the tomato plants. Irrigation was done as required with an equal volume of sterile water. Data were collected on disease incidence and severity, plant height (cm), number of leaves, yield quantity, fruit quality, and shelf life. Data collected were subjected to statistical analysis. Result obtained showed that T. harzianum significantly reduced the mycelial growth of each of the pathogens compared to T. viride. The interaction of solarization for two months and soil treatment with T. harzianum at 107spore/ml significantly reduced disease incidence and severity of the pathogens, increased plant height, number of leaves, yield quantity, fruit quality and enhanced shelf life of the fruits. The result of this study validated that the interactive effect of two months solarization and Trichoderma harzianum at 107 spore/ml effectively managed Fusarium wilt and Southern blight diseases of tomatoes than their application as sole management agents. Also, the shelf life of tomato fruits was significantly increased by this treatment.
