Efficacy of Certain Tribenuron-Methyl Formulations for the Control of Broad-Leaved Weeds in Wheat under Field Conditions

Abstract

Two field experiments were conducted during 2017-2018 and 2018-2019 seasons to evaluate the effect of eight tribenuron-methyl formulations (four as WG 75% and four as DF 75%) beside hand weeding (twice at 21 and 42 DAS) on broad-leaved weeds (BLWs) in wheat under field conditions. All the agricultural practices were carried out uniformly as recommended. All treatments were arranged in randomized complete block design and replicated four times each of 42 m2 (6×7 m). All formulations were applied at the rate of 8.0 gm fed.-1 in 200 L. water fed.-1 by Knapsack sprayer (CP3) at 30 days after sowing (DAS). After two months from sowing (2MAS) (one month after treatment, one MAT), weeds were collected from an area of 2m2 which was randomly selected from each plot (by using a square woody frame, 50 cm×50 cm). The removed annual BLWs were identified and counted for density as number m-2 and biomass [fresh weight gm m-2] in all treatments. In the untreated control, biomass, biomass%, density and density% for each BLW were recorded. The common prevailed annual BLWs in the experimental wheat field during both seasons were annual Sowthistle (Sonchus oleraceus L.), cheese weed, little mallow (Malva parviflora L.), chicory (Cichorium pumpilum Jacq.), dentated dock (Rumex dentatus L.), medic (Medicago intertexta (L.) Mill.), scarlet pimpernel (Anagallis arvensis L.), sea beet, wild beet (Beta vulgaris L.) and sweet clover, Indian melilot (Melilotus indica L.). The results clearly indicated that biomass and density were varied according to the dominant weed species and from season to another. The BLWs were the most dominant and also they were common in wheat fields and the biomass and density of BLWs were varied between years and weeds. The herbicidal treatments gave the minimum weed biomass and density and gave good weed control efficiency (WCE %) than hand weeding treatments. Granstar formulation completely controlled C. pumpilum weed (in the first season), A. arvensis, R. dentatus and S. oleraceus weeds (in the second season). Skylla formulation completely controlled M. parviflora and R. dentatus weeds in the first season. The tested tribenuron-methyl formulations did not cause complete control for B. vulgaris, M. intertexta and M. indica weeds in both seasons. In all cases, the herbicidal treatments increased significantly the biological yield, grain yield, straw yield, harvest index and thousand grain weight in comparison with untreated control. Also, Granstar, Skylla and Cash Cool herbicides were the most effective, while Ownostar was the least effective. We can concluded that, Granstar, Skylla and Cash Cool formulations are the most effective in controlling broad-leaved weeds in wheat field and consequently increased the grain yield.