The Insecticidal Activities of Dried Leaves Powder of Strychnos spinosa (L), Artemisia abrotanum (L) and Lantana camara (L) Against Sitophilus zeamais

AbstractMaize (Zea mays L) is a staple food in Tanzania but is confronted by the challenges of maize weevils in storage structure. The objective of this study was to determine the efficacy of botanical leaf powders of affordable and available plant leaves on the control of maize weevils in stored maize grains. The efficacy of plant leaf powders was evaluated against stored maize weevils, Sitophilus zeamais at the Institute of Pest Management’s laboratory at Sokoine University of Agriculture. Treatments consisted of three weights of botanical leaf powders of 5 g per 200 g of maize grains, 10 g per 200 g of maize grains, and 20 g per 200 g of maize grains that were thoroughly mixed in sampling glass jars to obtain concentrations (w/w) while 200 g of untreated maize grains were used as control and actellic super dust at 0.11 g in 200 g of maize grains was used as standard. The experiment was laid down in a complete randomized design (CRD) to determine the optimum dose of botanical formulations that were recommended for protecting maize against weevils. The data were collected at weekly intervals for all nine weeks after application. The findings indicate that among the botanicals, the mean percentage mortality rate of Sitophilus zeamais in maize grains treated with a botanical leaf of Artemisia abrotanum was highest at a dosage of 20 g/200 g, recording an average of 76.22% for all eight weeks after application. Strychnos spinosa leaf powder is the second at 20 g/200 g of maize grains, recording an average mean percentage of 69.17%. Even though the death percentage rates of the remaining botanical leaf powders were smaller, there was still a significant difference (p<0.001) with the untreated negative control Keywords: Sitophilus zeamais, Strychnos spinosa, Artemisia abrotanum, Lantana camara, Pesticidal plants, Negative control, Optimum dose