Bioefficacy of Murraya koenigii oil against Spilosoma obliqua and Spodoptera litura
Nitin Harishchandra Thodsare, Priyanka Bhatt and Rajesh Prakash Srivastava
The insecticidal and biorational properties of Murraya koenigii oil were tested at five different doses against fifth instar larvae of Spilosoma obliqua and Spodoptera litura. M. koenigii oil significantly reduced the larval weight gain of S. obliqua at all the doses, ranging from 127.8 to 47.3% at 2.5 to 0.5 µl/larva, in comparison to control. At the dosesof 2.5 and 2.0 µl/larva, a negative weight gain (0.053 and -0.016 g/larva at 2 days after feeding) was observed. The insecticidal activity was only 33%, pupation 66.6% and adult emergence 63.3% at 2.5 µl/larva. The same dose showed reduction in larval weight gain over control (-106.25%), resulting into 26.66% larval mortality against S. litura. The mean pupal weight at the higher doses was significantly reduced to 0.21 g. Pupation (50.0%) and adult emergence (43.3%) were also significantly reduced at 2.5 µl/larva. M. koenigii essential oil shows promising results as a biorational chemical for the control of these two insect pests of agricultural significance.