Effect of Sodom Apple (Calotropis procera) Leaves and Siamese Cassia (Senna siamea) Leaves against Maize Weevils (Sitophilus zemais) Causing Damage on Maize Storage in Bauchi Environment

Abstract

Maize (Zea mays L.) is a major cereal crop widely cultivated and consumed in Nigeria, serving as a staple food for humans, livestock feed, and raw material for agro-based industries. However, its storage is severely threatened by post-harvest losses caused mainly by insect pests, particularly the maize weevil (Sitophilus zeamais), which leads to significant quantitative and qualitative deterioration of stored grains. This study evaluated the insecticidal effectiveness of Calotropis procera (Sodom apple) and Senna siamea (Siamese cassia) leaf powders against maize weevils in stored maize under laboratory conditions in Bauchi environment, Nigeria. The experiment was conducted in the Agronomy Laboratory of the Department of Agricultural Technology, Federal Polytechnic Bauchi, using a Completely Randomized Design (CRD) with three treatments: 10 g of Calotropis procera leaf powder per 200 g of maize (T₁), 10 g of Senna siamea leaf powder per 200 g of maize (T₂), and an untreated control (T₃), each replicated three times. A total of 10 adult S. zeamais were introduced into each container and observations were recorded weekly for six weeks. Data collected included number of dead insects, number of live insects, and number of holes per seed. The data were analyzed using descriptive statistics and Analysis of Variance (ANOVA) at 5% probability level. Results showed that both botanical treatments significantly increased maize weevil mortality and reduced grain damage compared to the untreated control. Senna siamea consistently exhibited superior insecticidal activity, recording the lowest mean number of live insects (10.5) and the least grain damage (1.2 holes per seed), while also achieving complete suppression of live insects at the end of the storage period. Calotropis procera also demonstrated considerable insecticidal properties but was less effective than Senna siamea. The control treatment recorded the highest insect survival and greatest grain deterioration throughout the study period. The ANOVA results confirmed significant differences (p < 0.05) among treatments for all parameters assessed. The study concludes that both plant powders possess insecticidal properties, with Senna siamea being more effective. Therefore, these botanicals can serve as affordable, eco-friendly, and sustainable alternatives to synthetic insecticides for maize storage protection in Bauchi environment.