Aqueous extracts of plants are used to control weeds being inexpensive and
environment friendly. Present study was undertaken to investigate the effect of aqueous
extracts of Sonchus oleraceus L. on the red rice (Oryza punctata Kotschy ex Steud.)
emergence and initial seedling growth. Treatments included in the study were aqueous
extract of leaves, stem and fruit of Sonchus oleraceus at varying concentrations 0.25, 0.50,
1, 2, 4 and 8 % (w/v) along with distilled water as a control. The allelochemicals present in
the aqueous extracts showed stimulatory, inhibitory and hormetic responses depending
upon the concentration and the plant part used for extraction. Results depicted maximum
mean emergence time (5.26 days) and minimum germination index (1.67), germination
percentage (40%), seedling fresh weight (59 g) and dry weight (8 g) of red rice with
application of 8% aqueous extract of S. oleraceus fruit. However, 4% aqueous extract of S.
oleraceus fruit produced minimum root length (5.71). On the basis of this experiment, it is
concluded that 8% aqueous extract of S. oleraceus fruit can be used for controlling red rice
weed.