Abstract:
Weeds cause significant yield and quality loss in sesame crop. Therefore, the effects of preemergence herbicides and hand-weeding either alone or in an integrated form were
evaluated for effective and economic weed management in sesame at Guraferda and Menitshash districts, southwestern Ethiopia in 2023 cropping season. The study comprised 12
treatments: s-metolachlor: 1.0, 1.5 and 2.0 kg ha-1; pendimethalin: 1.0, 1.3 and 1.6 kg ha-1;
s-metolachlor and pendimethalin each 1.0 kg ha-1 plus hand weeding (HW) 5 weeks after
crop emergence (WAE), one HW 3 WAE, two HW 2 and 5 WAE, weed free and weedy
check) arranged in randomized complete block design with three replications. Weed flora in
the experimental fields consisted of broadleaved, grasses and sedges with the respective
relative densities of 59.6, 29.4, and 11.0% at Guraferda and 72.8, 15.3, and 11.9 % at MenitShasha districts Results revealed that s-metolachlor 1.0 kg ha-1 plus HW 5 WAE reduced
weed dry weight by 81.4% over weedy check. S-metolachlor 1.0 kg ha-1 supplemented with
one hand weeding 5 WAE had significantly higher number of capsules plant-1, thousand seed
weight, grain yield and aboveground dry biomass than the weedy check plots. The highest
grain yield (749.8 kgha-1) and highest net benefit (ETB 54,278.9 kgha-1) were recorded from
s-metolachlor 1.0 kg ha-1 plus HW 5 WAE, whereas, the lowest grain yield (357.1 kgha-1) was
recorded on untreated plot. Significantly higher grain yield (634.7 kg ha-1) was recorded at
Guraferda than at Menit-Shasha. Therefore, farmers could use s-metolachlor at 1.0 kg ha-1
followed by one hand weeding at five weeks after crop emergence to maximize economic
benefit. However, if there is labor scarcity and timely availability of the herbicide, pre
emergence application of 2.0 kg ha-1 of s-metolachlor should be used to ensure utmost
financial benefit. The effects of low dose herbicide combinations should be evaluated for
broad spectrum and effective weed management in sesame crop.
