Allelopathic¬ Effects of Wormwood (Artemisia annua) on¬ the Weeds of corn (Zea mays L.)

The allelochemicals or secondary plant metabolites when are released to environment, influence the germination and seedling growth of neighbor's weeds. The aim of this study was to investigate the effect of the extract of worm¬wood (Artemisia annua) on the number and mass of weed seedlings and their seed germination under laboratory conditions. The Worm¬wood extracts were considered with different concentrations (1.25 to 20%) on the germination and seedlings growth of Zea maize, Johnsongrass (Sorghum halepense), common lambsquarter (Chenopodium ¬album) and redroot pigweed (Amaranthus retroflexus) for 5 days. Results showed that with increasing concentration of worm¬wood extracts, their effects on reducing seed germination and seedling growth of the above mentioned plants was more severe. Comparison of extract effects with polyethylene glycol, revealed that reduction of Johnsongrass and common lambsquarter seed germination were attributed to the osmotic pressure of the extract, where as, inhibition of seed germination of redroot pigweed and corn was due to allelochemicals. Results showed the worm¬wood extract was more related to the allelopathic effect.