Dose–response studies were conducted under laboratory conditions
using sand as growth medium to determine the effect of
Artemisia oil on growth of test weeds (Singh et al., 2006b). Briefly,
15-cm diameter Petri dishes were lined with a layer of Whatman
No. 1 filter paper moistened with 8ml of distilled water. These
were treated with different amounts of Artemisia oil to get 5, 10,
25, and 50g oil/g sand. After treatment, ∼400 g sand was placed
on top of the filter circle, sown with test weeds (25 seeds each,
except 15 for C. occidentalis). One hundred milliliters of distilled
water was added to sand, and covered with lids. Petri dishes were
then sealed with Parafilm®. A set of Petri dishes without oil for
each weed species served as parallel control. Five Petri dishes were
maintained as replicates for each treatment and weed species in