Efficacy and Economic Assessment of Commercial <i>Beauveria bassiana</i> in Managing Cucumber (Cucumis sativus L.) Insect Pests in a Derived Savanna Agroecosystem

A study was conducted in 2021 and 2022 planting seasons to determine the effective and profitable optimum rate and frequency of Beauvaria bassiana application for managing insect pests on cucumber crop. Beauvaria application produced significantly lower densities of insect pests compared to the untreated plots. Although leaf and fruit damage were statistically similar in the treated plots, the values were lower than the untreated plots. Significantly higher fruit yield (14.43 tons ha-1 and 13.44 tons ha-1) was obtained when Beauvaria was applied at 8 kg ha-1 once-a-week relative to the control 2.26 tons ha-1 and 2.34 tons ha-1, 2021 and 2022, respectively, resulting in a corresponding increase of 84 % and 83 % over the control. The relationship between insect pest infestation and yield was negative and significant (r = -0.90 and r = -0.80). In addition, the highest profitability index of 1.00 was obtained when Beauveria was applied at 8 kg ha-1 once-a-week in both years.