2020, Vol. 8, Issue 4, Part B

author(s)
Ruhul A, Ahmed SMS, Siddique AB, Roushan Ara and Bachchu MAA

abstract
Epilachna dodecastigma (Wied.) is an important and serious pest of many crops and causes considerable losses both the quality and quantity of the crops output. The present study was conducted to evaluate the efficacy of three non edible oils from neem, pongamia and rohituka plants against the adult of Epilachna dodecastigma Wied. in the laboratory conditions (28±2 ⁰C and 75±5% RH). Four doses viz. 250, 200, 150 and 100 mg/ml along with control were used for the determination of adult mortality and the doses of 100, 75, 50 and 25 mg/ml along with control were used to determine the antifeedant activities. All the tested oils had toxic and antifeedant activities against epilachna beetle but rohituka oil was found the most toxic as compared to others. Rohituka oil showed the highest mortality (76.67%) in maximum dose (250 mg/ml) while neem oil showed the lowest average mortality (14.33%) in minimum dose (100 mg/ml) against adult beetles. Mortality percentages were also found directly proportional to the hour after treatments and dose dependent. The pongamia oil provided the highest antifeedant index (64.39%) but rohituka oil showed the lowest (11.15%). The lowest LD₅₀ values of 260.66, 170.90 and 132.62 mg/ml at 24, 48 and 72 HATs, respectively also indicated the highly effective rohituka oil against the adults of E. dodecastigma. Based on the mortality percentages, LD₅₀ values and antifeedant activities the order of the toxicity of the oils were found as rohituka > pongamia > neem oil. The results show the insecticidal potentiality of three non edible oil as a natual and cheaper source for the control of epilachna beetle.