| dc.description.abstract | Rice weevil, Sitophilus oryzae L. is one of the most destructive and notorious insect pests of
raw cereal in store. The experiment was conducted in the laboratory of the Department of
Entomology, Hajee Mohammad Danesh Science and Technology University (HSTU),
Dinajpur to evaluate the efficacy of five spices against rice weevil during March to August
2019. Ethanol was used as solvent to prepare extracts and four different doses (2.5,2.0,1.5
and 1.0 mg/ml)along with control were applied for their toxicity, repellency, and residual
effects. All treatments were replicated thrice. Results showed that all the extracts had toxic,
repellent and residual effects on rice weevil. Mortality at 24,48 and 72 hours after
treatments indicated chili extract possessed the highest mortality (29.33%) whereas the
lowest (10%) was in turmeric extracts. Mortality percentage was directly proportional to the
level of concentrations of extracts and to the exposure time as well. Considering all the
concentration and extracts, the order of toxicity was found as chili> black pepper> ginger>
turmeric> cinnamon. The chili, black pepper, cinnamon, turmeric and ginger spices extracts
had moderate repellent action against rice weevil. The chili extract showed the highest
repellency (85.83%) while the turmeric provided the lowest (61.64%). The highest
inhibition rate of egg (60.30%) and adult (72.72%), and seed infestation (64.41%) and the
lowest rate of egg (58.87%), adult (67.15%), and seed infestation (61.26%) were found in
chili and cinnamon, respectively. However, the toxic, repellent and residual effect of chili
extract was more effective against rice weevil among the all spices extracts applied. | en_US |
