<div style="text-align: justify;">Four plant oils at the concentrations of 2.5, 5 and 10% viz.; Jatropha, (Jatropha curcas) Ocimum, (Ocimum grattisimum) Kapoor, (Cinnamomum camphora) Lantana, (Lantana camara) were tested for the growth regulatory activities against 8 day old larvae of S. litura and S. obliqua larvae and plant oil composition testing by GC-MS analysis for selected oils. Among four oils J. curcas (10%) showed better results for both the insects while least effective were L. camara (2.5%) and C. camphora (2.5%) for S. litua and S. obliqua larvae respectively. J. curcas (10%) also showed highest terminal larval mortality followed by C. camphora &gt; O. grattisimum &gt; L camara for mentioned insects. The analysis of plant oils revealed the presence of over 43 compounds, contributed to 99.16, 92.78 and 94.97 % of the total tested oils (J. curcas, O. grattisimum and C. camphora) respectively. In tested oils by GC-MS analysis among other compounds in highest quantity terpenoids were found. These plant secondary metabolites can be the responsible factor for effect of plant oils against insect-pest growth and development or as plant based insecticides.</div>

Detrimental effect and GC-MS analysis of some plant oils against Polyphagous pests Spodoptera litura and Spilarctia obliqua

<div>Background: Greengram the most important pulse crops in India suffers a lot due to infestation of many lepidopteran caterpillars mainly at its reproductive stage. Spilosoma obliqua Walk. Arctiidae, Lepidoptera commonly called Bihar hairy caterpillar (BHC) is categorized as the most devastating. 
 
Methods: Field efficacy of nine new generation popular insecticides were tested in coastal saline zone of West Bengal against BHC in greengram (IPM 2-3) during 2021-2022. Leaf dip bioassay study of those selected insecticides were also conducted to compute the LC50 value against the field collected as well as laboratory reared F2 generation 3rd instar larvae of BHC. 
 
Result: All the test insecticides showed lethal effect towards BHC but the magnitude of protection over control was significantly higher in spinosad (70.92%) followed by flubendiamide (70.35%). Pyriproxifen+fenpropathrin (29.92%) was proved to be the least&nbsp; effective treatment followed by pyriproxyfen+bifenthrin (31.91%). As per LC50 value (ppm) flubendiamide showed the highest toxicity against BHC in respect of laboratory reared caterpillar and field collected caterpillar (4.49 and 6.71 respectively), while pyriproxifen+fenpropathrin the lowest (624 and 637 ppm). BHC was recorded as potent defoliator which was reflected in yield, while pod damage is not so pronounced.</div>

Detrimental effect and GC-MS analysis of some plant oils against Polyphagous pests Spodoptera litura and Spilarctia obliqua

Chemical Management of Spilosoma obliqua Walker in Greengram