| dc.description.abstract | The experiment was carried out in the laboratory of the Department of Entomology,
Hajee Mohammad Danesh Science and Technology University (HSTU), Dinajpur during
June to October 2017 to find out the toxicity, repellency and residual effects of
bishkatali, mutha and bothua weed extracts against rice weevil, Sitophilus oryzae. The
doses were 1.7680, 1.4144, 1.0608 mg/cm2
for their toxicity effect and 30, 40, 50 mg/ml
for repellency and residual effects against rice weevil. The result revealed that all the
weed extracts had direct toxic, repellent and residual effect on rice weevil in storage.
Average mortality percentage of rice weevil at 24, 48 and 72 hours after treatments
indicated that bishkatali weed extract possessed the highest mortality (45.00 %) and
bothua weed extract showed the lowest mortality (30.28 %). Mortality percentage was
also found directly proportional to the level of concentrations of weed extracts and to the
exposure period. Considering all the concentration and efficacy, the order of toxicity
level of weed extracts were found as bishkatali >mutha >bothua. The bishkatali, mutha
and bothua weed extracts had moderate repellent action on rice weevil. Bishkatali weed
extract showed the highest repellency (44.44 %) while bothua extract provided the
lowest repellency (35.56 %). Among the tested weed extracts, Bishkatali extract showed
the lowest number (17.16%) of F1 progeny production and lowest (2.667%) weight loss
whereas the highest number (44.00 %) of F1 progeny production and highest weight loss
(54.82%) were found in control | en_US |
