Field Evaluation of Aqueous Ginger (Zingiber officinale) Extract Concentrations for Suppression of Tomato Early Blight and Improvement of Fruit Yield

Abstract

Early blight causes significant yield losses in tomato in tropical and subtropical regions. Synthetic fungicides commonly used for the management have limitations such as high costs, inconsistent quality, risk of pathogen resistance, safety and environmental concerns that call for sustainable botanical alternatives. Thus, the study evaluated different concentrations of aqueous ginger (Zingiber officinale) extract for suppression of tomato early blight and improvement of fruit yield under field conditions. The experiment was conducted at the Research and Demonstration Farm of Enugu State Polytechnic, Iwollo, Nigeria. The treatments consisted of 0 (negative control), 5, 10, 15, and 20% v/v aqueous ginger extract, and Redforce (a.i. Metalaxyl 12% + Copper (I) oxide 60% WP) as standard positive control. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. Data were collected on incidence and severity of early blight, disease suppression, survival percentage, total fruit yield, and percentage of marketable fruits and subjected to Analysis of Variance (ANOVA) at 5% level of significance. Treatment means with significant difference were separated using Fisher’s Least Significant Difference (F-LSD) at 0.05 probability level. The results showed significant differences (p < 0.01) among the treatments in all the parameters evaluated. Aqueous ginger extract treatments significantly (p < 0.01) suppressed early blight development and increased total fruit yield and percentage of marketable fruits compared to negative control. The 20% v/v treatment recorded the highest performance among the ginger-extract treatments and suppressed early blight by 86.23% compared to the negative control and resulted in a 253.85% increase in fruit yield. It could be concluded from the findings of the study that aqueous ginger extract was effective in the management of early blight in tomato under field conditions. The 20% v/v aqueous ginger extract was the most effective treatment and could therefore be recommended as a botanical alternative for sustainable management of early blight in rainfed tomato production. However, further studies involving multi-location and multi-season evaluations are recommended to validate its performance under different production environments.