HERBICIDE INPUTS FOR A NEW AGRONOMIC CROP, ANNUAL WORMWOOD (ARTEMISIA-ANNUA)

Annual wormwood has been cultivated on a small scale for production of the artemisinin class of antimalarial drugs in sufficient quantities for preclinical and clinical trials. Large scale cultivation will require a reliable, efficient crop production system. Production systems using 32 herbicides alone or in combinations were evaluated in growth chamber, greenhouse, and field experiments at Stoneville, MS from 1985 through 1988. The herbicide treatments that provided the best weed control were (A) metolachlor at 2.2 kg ai ha-1 preemergence (PRE), (B) chloramben at 2.2 kg ai ha-1 (PRE), or (C) trifluralin at 0.6 kg ai ha-1 preplant soil incorporated (PPI) followed by fluazifop at 0.2 + 0.2 kg ai ha-1 postemergence broadcast (POST) and acifluorfen at 0.6 kg ai ha-1 (POST). These herbicide production systems provided excellent weed control (greater-than-or-equal-to 85%) and minimal crop injury (less-than-or-equal-to 10%) with no effect on crop height or weight at harvest. Production of artemisinin was not reduced by herbicide treatments A, B, and C in 1987 and treatments B and C in 1988 when compared with the hand-weeded plots.