Insecticidal Efficacy of Four Spices against Callosobruchus maculatus (F.) and Sitophilus zeamais (Mostch.) Adults in the Laboratory
Ajelara, Kafayat Oluwakemi
*
Lagos State University, Ojo, Lagos State, Nigeria.
Alafia, Azeezat Oyindamola
Lagos State University, Ojo, Lagos State, Nigeria.
Ani, Godwin
Department of Zoology and Environmental Biology, Lagos State University, Lagos State, Nigeria.
Denloye, Abiodun Akinpelu
Lagos State University of Science and Technology,Ikorodu, Lagos State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Aim: Chemical insecticides have been reported to cause health hazards; such as cancer, bioaccumulation, discomfort and allergy when applied on stored food produce. These has led to the search for a safer alternatives in the control of insect pests. Hence, this research was evaluated for the toxicity of four spices; Capsicum annuum and Capsicum frutescens, Curcuma longa, and Piper nigrum against bean and maize weevil.
Study Design: Conventional bioassay.
Place and Duration of Study: The study was conducted at Lagos State University, Nigeria between January and July 2023, and all the spices and grains used were collected from within the State.
Methodology: Adults of both insect pests were introduced into disposable cups containing the treated grains of various concentrations and control. Probit software was used to analyze the results and determine lethal concentrations of 50% mortality.
Results: The results showed that the four spices were all effective against both test insect pests, and the powder being more effective than the whole form. The most lethal test spice on C. maculatus at 48hrs were the powder and essential oil of C. annuum fruits with LC50 values of 36.61g/kg and 0.44µl respectively. While C. annuum fruits was the most toxic to S. zeamais with LC50 value of 176.40g/kg. The least lethal test spice on C. maculatus at 48hrs was the whole form of P. nigrum seeds and the essential oil of C. longa rhizomes with LC50 values of 481.86g/kg and 1.89µl respectively. The least lethal test spice on S. zeamais was the whole form of C. frutescens fruit which was barely toxic to the maize weevils. Mortality also increased with increased exposure time and concentration.
Conclusion: This study showed that the four test spices are effective in the control of both insect pests. It is recommended that C. annuum should be used as a substitutes to chemical insecticides for the control of insect pests.
Keywords: Botanicals, stored insect pests, Callosobruchus maculatus, Sitophilus zeamais, Capsicum annuum, Piper nigrum