Comparative efficacy of sweet orange, Citrus sinensis(l) rind powder and oil for the control of maize weevil, Sitophilus zeamais (motschulsky).
Sweet orange, Citrus sinensis((L.) rind powder and oil were evaluated for the control of maize weevil, Sitophilus zeamais(Mot.) under ambient laboratory conditions (28 ± 2o C and 75 ± 20% R.H.). Experiments consisted of exposing adult S. zeamais to both the powder and oil for 42 days. Mortality counts were taken from the first day after treatment (DAT) until 42 DAT. The result indicated that pulverized orange rind had no significant mortality effect on adult S. zeamais (P≥0.05) resulting in severe damage of the grains and weight loss. The Weevil Perforation Index (WPI) for all the dosages of the powder was greater than 50%, indicating reduced protectant effect; while the rind oil treatment resulted in significant mortality of adult S. zeamais (P≤ 0.05). There was significant reduction of grain damage when protected with oil extract. The WPI of all the dosages was below 50%, which confirmed the efficacy of the orange rind oil. The C. sinensis rind oil, not the powder can therefore be used for the storage of maize grains.
Agro-Science Vol. 7 (1) 2008: pp. 9-14