An evaluation of the efficacies of four (4) selected herbicides in controlling herbicide resistant weeds in cassava cultivation in Bebi Obanliku, cross river state, Nigeria

A two year (2024 and 2025) trial was conducted at the Teaching and Research farm of the Federal College of Education Obudu, (Bebi Campus) Cross River State. The main objective was to compare the efficacies of four (4) selected herbicides in controlling noxious/herbicide resistant weeds in cassava varieties. The design of the experiment was a Completely Randomized Design (CRD) on a four by four (4 x 4) factorial layout. The main plot treatments were the cassava varieties; TMS. 60444, TMS. 30555, TMS. 30572 and TMS. 60506. The subplot treatments were the herbicide types; Paraquat, Glyphosate, Atrazine, and Ametryn, all applied at 3.0 kg/ha. Application was done two weeks after planting of the cassava varieties. Data for percentage establishment of cassava were taken at four (4) weeks after planting (4WAP). Herbicide toxicity (injury) on the cassava and the weed control efficiency were recorded six (6) weeks after planting (6WAP). Tuber yield in tons per hectare (t/ha) were recorded at six (6) months after planting (6MAP) all data generated were subjected to analysis of variance (ANOVA) and the means were separated using Least Significant Difference (LSD) at 5 % level of probability. Results showed that herbicide toxicity rating on the cassava was higher in Atrazine> Glyphosate> Paraquat> Ametryn. Weed control efficiency rating of herbicides was Paraquat (97.40 %)> Glyphosate (85.87 %)> Ametryn (83.83 %)> Atrazine (62.07 %). The highest yields in t/ha were recorded in TMS. 30572 (4.30 t/ha) in application of Paraquat and (3.88 t/ha) in application of Glyphosate. Glyphosate and Ametryn gave significantly higher yields in almost all the varieties. Therefore it was recommended that Paraquat applied at 3.0 kg ai/ha should be the correct approach to dealing with noxious/herbicide resistant weeds. Two varieties of cassava TMS. 30572 and TMS. 30555 were also recommended to farmers.