Repellent and Fumigant Activities of Tanacetum nubigenum Wallich. ex DC Essential Oils against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae).

The repellent and fumigant toxicity of essential oils of Tanacetum nubigenum Wallich. ex DC collected from three different habitats (Gothing, Burphu and Glacier) of Uttarakhand Himalayas, India named as TNG, TNB and TNM respectively, were investigated against the adults of red flour beetle Tribolium castaneum (Herbst). Among the three samples tested, TNG was found to more potent exhibiting more repellent effect towards the insects and with LC50 values by fumigant bioassay were 13.23 and 8.32 µl per 0.25 L air at 24 and 48 h exposure of insects to the essential oil respectively. In between other two oil samples, TNM was superior in potency showed LC50 value of 14.22 (24 h) & 8.82 µl per 0.25 L air (48 h). During in vivo study all the essential oil samples significantly protected 500 g of wheat grains for 6 months from insect infestation as compared to non fumigated grains and order of efficacy was TNG>TNM>TNB. There were no side effects of essential oils on germination rate of grains (<85%) exposed for 6 months after fumigation. The present study suggests that essential oil of T. nubigenum can be explored as novel natural fumigants for the control of stored product insects.

Constituents of Artemisia indica Willd. from Uttarakhand Himalaya: A source of davanone.

BACKGROUND: The genus Artemisia is important due to its medicinal properties as well as vital aroma compounds of commercial value. OBJECTIVE: The aim of the study was to explore the potential of the essential oil of Artemisia indica wildly growing in Uttarakhand. MATERIALS AND METHODS: The aerial parts of Artemisia indica Willd. (Asteraceae), collected from wild growing habitat of Garhwal Himalaya, Uttarakhand (north of India) at full flowering stage were hydro-distilled and gave pale yellow oil with the yield of 0.8% (v/w). The obtained essential oil was analyzed by GC and GC-MS and identified 32 components, amounting 95.42% of the oil. RESULTS: Among detected compounds, the principal component was found to be davanone (30.80%), followed by ß-pinene (15.30%) and germacrene-D (5.82%). CONCLUSION: To the best of our knowledge, this is the first report on A. indica from Himalayan region of India, which detected davanone as major component. The species, collected from a specific location, can be explored for isolation of davanone for its industrial utilization and as alternate source of Artemisia pallens, which have already established commercial value.