Response of tomato plants to three different levels of urea and chemical control in suppressing root rot disease caused by the fungus Rhizoctonia solani improving growth characteristics, and increasing yield.

• Firas Hamad Awad

  Author

The current research work was performed in the greenhouses of the College of Medicinal and Industrial Plants of the University of Kirkuk. The purpose of the work was to evaluate the response of tomatoes to three urea fertilizer levels (80, 160 and 200 kg·ha⁻¹) and two concentrations (0.1 % and 0.15 %) of the chemical fungicide Beltanol (contains the active component of 8-hydroxyquinoline sulfate 50%) against root rot disease caused by Rhizoctonia solani and improve certain growth and productivity characteristics. The research was performed using the RCBD design (three replicates). The characteristics investigated included disease severity, yield, weight of fruits, root length, leaf number, and leaf area. The research results showed a significant influence of the level of urea, fungicide concentrations, and the interaction between them on all the investigated characteristics. In terms of the response to the investigated characteristics, the level of urea fertilizer of 160 kg ha⁻¹ was found to be the best; it gave the minimum mean severity of infection (15.16 %) and the maximum mean values for the yield (1.014 kg plant⁻¹), weight of fruits (45.94 g), and root length (24.38 cm). In addition, the use of this level of fertilizer also gave the maximum mean values for the leaf number (28.11 leaves plant⁻¹) and leaf area (860.71 cm² plant⁻¹). The use of the Beltanol fungicide at a concentration of 0.15 % lowered the mean severity of infection to 16.85 % and increased the growth and yield characteristics compared to the control (without the fungicide). The interaction between the 160 kg ha⁻¹ urea fertilizer level and 0.15 % of the Beltanol fungicide concentration gave the best results. It gave the minimum severity of infection (8.10 %) and maximum values for the fruit weight, root length, leaf number, and leaf area (48.31 g, 29.43 cm, 32.00 leaves plant⁻¹ and 987.37 cm² plant⁻¹), respectively. The maximum total yield (1.077 kg plant⁻¹) was achieved at the urea level of 160 kg ha⁻¹ together with the fungicide concentrations of 0.1 % and 0.15 %. Therefore, it can be concluded that the application of the 160 kg ha⁻¹ urea level and the Beltanol fungicide at a concentration of 0.15 % is the optimal treatment against the root rot caused by the fungus R. solani in tomato plants.

• pdf