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Abstract
Trials were conducted under controlled conditions to determine the tolerance of young papaya plants (15 cm tall) to postemergence herbicides. Initial screen trials included paraquat (1.68 Kg ai/Ha), MSMA (2.24 Kg ai/Ha), 2,4-D (4.26 Kg ai/Ha), bromoxynil (0.28 Kg ai/Ha), atrazine (2.24 Kg ai/Ha), cyanazine (1.12 Kg ai/Ha), dimethenamid (1.12 Kg ai/Ha), endothal (0.56 Kg ai/Ha), imazameth (0.067 Kg ai/Ha), imazethapyr (0.028 Kg ai/Ha), acifluorfen (0.28 Kg ai/Ha), lactofen (0.12 Kg ai/Ha), oxyfluorfen (0.03 Kg ai/Ha), and bentazon (1.12 Kg ai/Ha) as well as an untreated control. Atrazine, bentazon, cyanazine, imazethapyr, imazameth and dimethenamid caused, low toxicity at the rates used and dry weights of treated plants were equal to the untreated control. Other herbicides caused severe injuries followed by total death at 10 days after treatment. In the herbicide rate trails, these six screened herbicides were tested along with metribuzin (0.25 Kg ai/Ha), linuron (0.75 Kg ai/Ha) and DCPA (9.00 Kg ai/Ha) at Vi, 1, 2 and 4X rates. Imazameth when applied over-thetop did not significantly reduced papaya weight at the 2X rate when measured 21 days after treatment, whereas 4X rate reduced shoot dry biomass in approximately 40%.