Effect of Botanical Powders on controlling Pulse Beetle (Callosobruchus maculatus Fabricius) in cowpea (Vigna unguiculata) seeds under Laboratory Conditions

Purpose: Adverse impacts of the application of synthetic pesticides, especially in stored grains, necessitate considering alternate and safe methods for managing pests such as Callosobruchus maculatus in warehouses. Therefore, the potential of various indigenous plant extracts was tested against C. maculatus under laboratory conditions.
Research Method: Leaves of Azadirachta indica and Mentha longifolia, fruits of Citrullus colocynthus, Allium sativum, and Trigonella foenum-graecum seeds at a rate of 2 grams in 100 grams of cowpeas along with aluminum phosphine tablets were applied in separate jars that contained 5 fresh pairs of C. maculatus. Observations were taken at 24 hours, 48 hours, and one week for the toxicity of botanicals, whereas the population of beetles was also recorded monthly for three months.
Findings: All botanicals were found to be effective in causing mortality of C. maculatus adults. M. longifolia, A. indica, and C. colocynthus caused 100% mortality of targeted C. maculatus within one week, whereas aluminum phosphine took only 24 hours to kill all beetles with no further population development. A gradual rise in C. maculatus population was recorded in T. foenum-graecum and A. sativum treatments, whereas a slow growth was recorded in M. longifolia and A. indica. The highest population and maximum weight loss were recorded in the control, whereas M. longifolia and A. indica treatments suffered lower losses.
Originality/value: All the botanicals were found effective against C. maculatus, with M. longifolia and A. indica being the most effective; hence, they may be applied for its management in warehouses.