Evaluation of the Efficacy of Some Pre-Emergence Herbicides in Cotton (<i>Gossypium Spp.</i>) in Northern Ghana

Abstract

A field experiment was conducted at the Savanna Agricultural Research Institute to investigate the effects of pre-emergence herbicides for weed control in cotton during the 2014 and 2015 cropping seasons. The study determined the effects of different rates of three novel cotton herbicides with different formulations on weeds, yield components and yield of seed cotton, applied as pre-emergence. The treatments were laid out in randomized complete block design with four replications and consisted of Diflufenican + Flufenicent and Diflufenican + Flufenicent + Flurtamone as 500SC formulations of each and applied at the rate of 0.3, 0.4, 0.6, and 0.8 l/ha, whilst Diflufenican + Flufenicent + Flurtamone as 200SC formulation was applied at 0.4, 0.5, 0.8, and 1.0L/ha. A reference herbicide + product with active ingredients Promotrin + Metolachlor applied at 3.0l /ha and untreated weedy and weed free checks were included.  Results showed that. Diflufenican + Flufenicent + as 200SC applied at 0.8 l/ha gave the lowest weed dry weight (65.0 g/m²) similar to the reference herbicide (189.4 g/m²) and Diflufenican + Flufenicent + Flurtamone as 200SC applied at 0.8 l/ha (144.8 g/m²), whilst weedy check gave highest (548.7 kg/m²). Consequently, Diflufenican+ Flufenicent applied at 0.8 l/ha gave significantly (p<0.05) the highest number of bolls and number of opened bolls than the reference herbicide; but similar to weed free. Diflufenican + Flufenicent +Flurtamone as 500SC, applied at 1.0 l/ha supported tallest plants similar to Diflufenican + Flufenicent + Flurtamone as 200SC at 0.4 and 0.6 l/ha and Diflufenican + Flufenicent as 500SC applied at 0.6 and 0.8 l/ha and better than the reference herbicide. Diflufenican+ Flufenicent as 500SC applied at 0.8L/ha (81.3 %), Diflufenican + Flufenicent + Flurtamone as 500SC   at 0.8 l/ha (78.7 %) and the reference herbicide (76.3 %) did better (90 %) than weed free. Generally, early control of weeds with the tested herbicides using 0.4 to 1.0 l/ha minimized weed growth and supported high seed cotton yields.