Knowledge of distribution, density, and abundance of weed in a place is a prerequisite for its proper management. Parthenium hazard is a national agenda in Malaysia, and Kedah is the worst infested state in the country. Despite it, the distribution and abundance of the weed is not systematically documented. Periodical weed surveys were conducted at Kuala Muda, Kedah, during March and September 2015 to identify infested locations, to determine density, abundance, and severity of infestation, and to do mapping of weed distribution of the area. Geographic locations were recorded using a GPS. Weed density was measured following the list count quadrat method. e mapping of weed infestation was done by the ArcGIS software using data of GPS and weed density. Different letters were used to indicate the severity of infestation. Results indicated that in Kuala Muda, sixteen sites are infested having average weed density of 10.6 weeds/m 2 . e highest density was noted at Kg. Kongsi 6 (24.3 plants/m 2 ). e relative density was highest at Semeling (27.25%) followed by Kg. Kongsi 6 (23.14%). e average severity of infestation was viewed as the medium. Parthenium abundance and relative density increased by 18.0% and 27%, respectively, in the second survey conducted. e intervention of concerned authority to tackle the weed problem using integrated weed management approach is emphasized.

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To mitigate environmental pollution and food contamination caused by inappropriate and excessive herbicide usage, most potent herbicides should be screened to control rice weeds. A research trial was executed for assessing the comparative efficacy of different herbicides to control rice field weeds and to evaluate the toxicity on rice under normal (distilled water) as well as different salinity levels (4 and 8 dS m−1). The study was designed to select the most potent herbicide and its appropriate dose for weed control of rice crop in coastal areas. Fourteen herbicidal treatments were included weed free crop, Pretilachlor (0.25, 0.50, 0.375 and 0.75 kg a.i. ha−1), Propanil + Thiobencarb (0.6 + 1.2, 0.9 + 1.8, 1.2 + 2.4 and 1.8 + 3.6 kg a.i. ha−1), Bensulfuron + MCPA (0.03 + 0.05, 0.045 + 0.075, 0.06 + 0.1 and 0.09 + 0.15 kg a.i. ha−1) and weedy check (control). The results revealed that all tested herbicides in higher than recommended doses for non-saline rice fields were effective in controlling Cyperus iria, Echinochloa colona (salt-tolerant) and Jussiaea linifolia but showed in light injury in rice plants grown in non-saline soils. These higher doses of herbicides recorded severe crop injury under saline conditions indicating their differential efficacy from normal non-saline conditions. Treatments including Pretilachlor (0.375kg a.i. ha−1), Propanil + Thiobencarb (0.9 + 1.8 kg ai/ha), Bensulfuron + MCPA (0.06 + 0.1 kg a.i. ha−1) and Pretilachlor (0.50 kg a.i. ha−1) remained superior in terms of weed control and grain yield production under all salinitylevels at TanjungKarang, Malaysia. It is concluded that herbicides respond differently under saline conditions and optimization of their doses potentially prevent herbicidal injury in rice plants.

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Field experiment was carried out at the Bangladesh Agricultural Research institute, Joydebpur, Gazipur during 2010 to 2011 to identify suitable legume crops with maize in maize + legume intercropping systems for better weed suppression, productivity and economic benefits in Rabi season.  There were 17 treatments of which two sole crop of hybrid maize (Zea mays BARI Hybrid bhutta -9) (weed free and no weeding), three weed free sole crops of pea (SN), bushbean (SN) and cowpea (SN) in Rabi season, and their intercropping. Twelve intercropping with different weeding regimes (no weeding, one hand weeding at 20 days after emergence (DAE), one hand weeding at 40 DAE, and two hand weeding at 20 and 40 DAE of maize-legume intercropping under normal row (75 cm Î 25 cm), and two rows of legumes in between two rows of maize were used . Among all intercropping, maize-pea with two hand weeding at 20 and 40 DAE gave the lowest (6.57 g m-2 at harvest) weed dry weight and the highest weed control efficiency (86% at harvest). Maize-pea with two hand weeding at 20 and 40 DAE gave the highest yield (maize: 7.58 t ha-1; 6.27 t ha-1 pea), resource complementarily and profitability (LER = 1.89, BCR = 4.19). Intercropping of two rows of pea in between two rows of maize with two hand weeding at 20 and 40 DAE to be a promising practice for weed suppression and profitable maize + legume intercropping in Rabi season. Bangladesh Agron. J. 2018, 21(2): 33-44