Study on weed flora and their influence on patchouli (Pogostemon cablin Benth.) oil and patchoulol

Experiments were conducted to study the weed flora and its influence on the yield of oil and Patchoulol by co-distillation of fresh Patchouli leaves with weed biomass at different proportions (0, 5, 10, 15 and 30%) during 2004-05 and 2005-06. The survey of weeds commonly growing in patchouli plantation was made and a total of 17 weed species were recorded. Alternanthera sessile, Cynodon dactylon and Oxalis cornicullata exhibited 100% frequency in both the years. A. sessile, C. dactylon and O. cornicullata had highest density during 1st year and the density of most of the weed species increased during 2nd year except C. dactylon and A. sessile. Co-distillation of fresh Patchouli leaves with weeds at the rate of 0, 5, 10,15 and 30% yielded 0.70, 0.67, 0.65, 0.50 and 0.43% oil, respectively. It was observed that the oil yield decreased gradually with the increase in weed biomass. However, the percentage of patchoulol showed a different behaviour. It decreased at 15% (53.7) and 30% (50.4) and increased at 5% (56.5) and 10% (63.8) treatments. The oil extracted with weed biomass imports a weedy odour, which may decrease its commercial value. © Academic Journals Inc