Best way to control Parthenium (congress grass / gajar ghas)?

Parthenium (congress grass, gajar ghas) is an aggressive invasive weed that spreads fast on bunds, roadsides, fallow land and wastelands, produces huge numbers of seeds, and can cause skin allergy and breathing problems, so handle it carefully with gloves and a covered face. Control works best by stopping it from seeding and using several methods together. The single most important rule is to pull, cut or spray it before it flowers and sets seed, because once it seeds the problem multiplies. For small areas and bunds, uproot it (wearing gloves) when the soil is moist, and do this repeatedly. On non-crop land like roadsides and fallow, a registered post-emergence herbicide can be used, and common salt solution or registered products are sometimes used on waste areas, but always follow label and local guidance. In crop fields use the herbicide recommended for that specific crop. A useful biological tool is the Mexican beetle (Zygogramma), released in some areas to feed on parthenium, and growing competitive plants like marigold or dense fodder crops can crowd it out. Community action matters because seed blows in from neighbours, so clearing it together along the whole village belt works far better than one farmer fighting alone. Use only herbicides registered for the situation, follow the label, and confirm with your KVK or agriculture department, as some products are only meant for non-crop land.