Weed control on growth, yield, and physicochemical properties of tarragon

ABSTRACT

Competition from weeds limits tarragon (Artemisia dracunculus L.) production. Field experiments were conducted for two consecutive seasons to evaluate methods of control on weed populations and growth, yield, and oil quality of tarragon. Pendimethalin, metribuzin, and oxyfluorfen, alone, or in combination with rye mulch, were examined for weed control and effects on yield and oil quality. The greatest yield, and essential oil content, were from the weed-free treatment. Pre-emergence application of pendimethalin, which is not yet cleared for use in tarragon, at 0.5 and 1.0 kg∙ha⁻¹ ai, in combination with 1 hand-weeding, or rye mulch, provided higher yields than no weeding. Rye mulch alone, or weeding twice manually, was not as effective. The lowest content of the essential oil methyl chavicol was in plants grown with no weeding, the highest was for the weed-free treatment. Integrating reduced herbicide with hand weeding, or mulch, may lower herbicide use to provide adequate weed control and produce acceptable yield and essential oil content. It needs to be clarified whether there is a residue above acceptable limits in tarragon tissue which could pose a health hazard to humans.

KEYWORDS:

• Artemisia dracunculus
• dry yield
• Iran
• methyl chavicol
• oil content
• mulch pendimethalin
• rye