Eggplant (Solanum melongena) is an excellent nutritional legume-fruit were cultivation faces challenges from pathogens. Organic alternatives like Tithonia diversifolia and Ageratum conyzoides extracts, known for antimicrobial and growth-promoting properties, offer potential sustainable solutions, reducing reliance on chemical fertilizers and pesticides. This study aimed to evaluate the efficacy of liquid extracts from Tithonia diversifolia and Ageratum conyzoides on the growth and disease resistance of eggplant.
Between March and June 2024, a field experiment was conducted in Njombe, Njombe-Penja Subdivision, Moungo Department, Littoral Region of Cameroon. The study included five treatments: T1 (negative control, no amendment), T2 (Tithonia diversifolia extract), T3 (Ageratum conyzoides extract), T4 (a combination of both plant extracts), and T5 (positive control, amended with NPK 20-10-10 fertilizer). The treatments were arranged in a completely randomized block design on an established plot.
Data collected on stem height, collar diameter, number of branches, leaf count, leaf area, floral buds, fruit count, fruit weight, fruit yield, leaf damage (disease severity and progression rate), chlorophyll pigment content, water content, and mineral content were subjected to analysis of variance (ANOVA). Where significant differences were observed, multiple mean comparisons were performed using Duncan’s test.
The results revealed that the extracts from Tithonia diversifolia and Ageratum conyzoides significantly improved stem height, collar diameter, fruit weight, biochemical growth, and reduced disease severity and progression. The highest stem height was recorded in the T4 treatment (19.84 cm) and T5 (19.27 cm), while the lowest was in the negative control T1 (14.87 cm). Collar diameter was significantly greater in T4 (0.845 cm) and T5 (0.840 cm), compared to the smallest in T1 (0.777 cm). Fruit weight was highest in T3 (145.8 g) and lowest in T1 (31.41 g). Carotenoid content was highest in T4 (3044.92 mg/ml) and lowest in T5 (2366.13 mg/ml).
Disease severity was significantly lower in T4 (4.919%) and highest in T1 (6.88%). Disease progression rate was most pronounced in T1 (27.33%) and least in T4 (11.65%) and T5 (11.06%).
This study demonstrates the potential of Tithonia diversifolia and Ageratum conyzoides extracts as effective organic amendments to promote the growth and enhance the disease resistance of eggplants.
Keywords: Ageratum conyzoides, Eggplant, Liquid Extracts, Phytopathology Tithonia diversifolia