Response of Golden Torch (Heliconia psittacorum × spathocircinata) to Pre-emergence Herbicides (Primextra Gold® and Gardoprim A®) and Their Effectiveness on Weed Control

Abstract

Field experiment was conducted at the Teaching and Research Farm of the University of Port Harcourt in 2012 to evaluate the response of Golden Torch (Heliconia (psittacorum × spathocircinata) and weeds to Primextra-Gold ® (Atrazine 370 g/l + Metolachlor 290 g/LSC and Gardoprim A®   (Terbutylazine 250 g/l + Atrazine 250 g/l)]. The experimental design was split plot with 3 replicates. The herbicides was applied pre-emergence/pre-plant and planting was done at 0, 4, 8, 12 and 16 days as the main plot, while herbicide dose (0, Primextra Gold® at 4.5 L/ha and Gardoprim A at 6.0 L/ha) was the sub plot. Growth parameters of Golden Torch assessed at 12 weeks after transplanting (WAT) were: sprouting, plant height, leaf area and number of leaves while the weed parameters evaluated were: density and dry biomass. Result showed that the treatments significantly (P <  0.05) affected weed growth with mean weed density averaging: 29, 48 and 162 weeds/m2 for   Primextra Gold® , Gardoprim A® and untreated control respectively. Weed biomass reduction was in order of, Primextra Gold® (27.57 g/m2) < Gardoprim A® 31.01 g/m2< untreated control (39.72 g/m2). Herbicide treatments significantly affected Golden Torch rhizomes sprouting (average = 42.5%) compared to the untreated control plot (67%). Rhizomes sprouting was significantly high in herbicide dose (73.1%) and lowest (26.85%) in the untreated control at 16 DAP. Days of planting after herbicide application (DAP) did not differ significantly on the growth parameters except on leaf area where 12 DAP  treatment had the highest leaf area of 121.3 cm2 followed by 16 DAP (116.20 cm2). There were no significant interactive effects between herbicide dose and days of planting after herbicide application on the Golden Torch growth parameters. The result of this study showed that Primextra-Gold and Gardoprim A could be used in commercial Golden Torch production; and that Golden Torch could be planted between 12 and 16 and days after herbicide application.