A comparative analysis of the efficacies of six selected herbicides for effective control of spear grass (Imperata cylindrical Linn) in cassava production in Obudu, Northern Cross River State

A two-year, (2015 and 2016) field trial was conducted in Obudu Local Government Area of Cross River State to compare the efficacies of six (6) selected herbicides in controlling spear grass (Imperata cylindrical Linn) in cassava farm. The main treatments were the three cassava varieties: TMS 30572, TMS 50395 and NR 8082, while the sub treatments were six herbicides: Primextra, Igrancombi Gold, and Paracot as pre-emergence, Touchdown Forte Hi Tech, Galex and Fusilade Forte as post-emergence herbicides. The result showed that cassava establishment did not differ significantly among the cassava varieties, whereas herbicide type significantly (p<0.05) affected cassava establishment. High plant establishment was recorded in plots treated with Paracot, followed by plots treated with Igrancombi compared to high mortality rate recorded in plots treated with primextra as pre-emergence application. The tuber yield did not differ significantly among the cassava varieties. However, on the basis of average for both years, the trend was as follows: TMS 30572 (2.81 t/ha-1) > NR 8082 (2.75 t/ha-1)> TMS 50395 (2.56t/ha-1). On the contrary, tuber yield differed significantly (p<0.05) among herbicide types irrespective of the cassava variety, although no well-defined trend was established.