Evaluation of the efficacy of different herbicides for controlling grass and broadleaf weeds in potato (Solanum tuberosum L.)

To study the efficacy of some new registered herbicides for controlling potato weeds, two field and greenhouse experiments were conducted in Damavand, Tehran. Both experiments were established as randomized complete block design with four replications. Treatments were prosulfucarb EC 80% at 2, 3, 4 and l ha-1, metribuzin WP 70% at 750 g ha-1, pendimethalin EC 33% at 3 and 5 l ha-1, rimsulfuron DF 25% at 40 and 60 g ha-1 plus cytogate at 2.5% v/v, paraquat SL 20% at 3 l ha-1, and no- herbicide application as control plot. Each plot was divided into two equal 4m halves. Herbicides were applied in one-half, and the other half was kept as its weed-infested control. Samplings were done at 15, 30 and 45 days after herbicide application (DAHA) in both halves of all plots, and weeds were counted based on species, over-dried and weighed. Visual rating of weed control was also done in each sampling. As no grass weed grew in the field experiment, the effects of herbicide treatments on barnyard grass (Echinochloa crus-galli), green foxtail (Setaria viridis) and Johnson grass (Sorghum halepense) were studied in the greenhouse experiment. Germinated weed seeds and potato seeds were planted in pots. Treatments were same as in the field experiment. At 15, 30 and 45 DAHA, percent survived weeds were assessed in each pot. All herbicide treatments had significant effects on weed control (P < 0.01) and potato tuber yield (P < 0.05). Paraquat at 3 l ha-1, rimsulfuron at 40 and 60 ha-1 plus cytogate at 2.5% v/v and metribuzin at 750 g ha-1 were the most effective treatments on broadleaf weeds. Pendimethalin at 3 and 5 l ha-1 showed the best performance for controlling grass weeds in addition to the aforementioned herbicides.