Efficacy of Jatropha curcas extracts amended with sulphur against Aspergillus flavus and Aspergillus ear rot on maize at harvest

Abstract

Jatropha curcas (Euphorbiaceae) is often considered a “miracle plant” due to its multiple uses, including its extracts reported insecticidal and fungicidal effects. This study assessed the efficacy of aqueous extract from dried leaves of J. curcas and Sulphur 99.5% WP fungicide in managing Aspergillus flavus growth and Aspergillus ear rot (AER) in maize at harvest across two sites. Treatments included botanical extracts at 300 g/L (T1), 350 g/L (T2), Sulphur at 5 g/L (T3) and 10 g/L (T4), and combinations of botanical extracts with Sulphur at both low and high concentrations (T5 and T6). Additionally, Aflasafe TZ01™ and untreated control were used as checks. At site 1, T2 and T6 significantly reduced AER incidence (10% and 13.33%, respectively) compared to the untreated control (70%). At site 2, most treatments, particularly the combinations of botanicals and sulphur, had lower AER incidences than the control. All treatments significantly reduced AER severity at site 1, where the untreated control exhibited the highest severity (67%). A similar trend was observed at site 2, although Aflasafe showed severity levels comparable to the control. Significant differences in A. flavus population counts were observed among treatments at both sites, with higher dosages of botanical extracts and their combinations with sulphur showing lower counts than the untreated control. The counts, in Colony Forming Units per gram (CFU/g), ranged from 171.5 (T6) to 490.9 (untreated control) and 80.5 (T6) to 554.4 (untreated control) in sites 1 and 2, respectively. These findings indicate that Jatropha curcas, either alone or in combination with sulphur, hold potential as a component of integrated management strategies against Aspergillus flavus infections at the pre-harvest stage.