There are, however, a lot of related issues to be taken into account while planning mass destruction of any vegetation. For instance, argemone mexicana seeds may be toxic from the edible oil point of view because the toxic seeds get mixed up with the edible mustard oilseeds. That does not mean that the seeds do not have any use at all. Argemone seeds do find use in homoeopathic as well as ayurvedic medicines, Gautam said.

From an agricultural point of view, argemone seeds do fall under the category ofunwanted vegetation which is a winter (rabi) crop, particularly in the northern parts of the country.

Farmers in Punjab and Haryana are found to be using various herbicides to destroy the argemone growth at their fields. But such a filed-level destruction of the plant is not a complete remedy, as there is continuous transit of argemone seeds through wind, water or animals into the cultivated agricultural lands, Gautam says.

Argemone mexicana is not the only culprit. Other toxic plants like xanthium strumarium - gokhru - and parthanium hysterophorous - congress grass - are also found in many places in the country.

There are different herbicides for different weeds. Well-known brands in the market are Basalin containing fluchloralin formulation. Then stomp containing pendimethalin formulation is also available in the market.

If argemone mexicana seeds are found in wheat crop, a chemical like dichlorophenoxy acetic acid - 2 , 4-D - can be applied whereas if the same argemone seeds are found in mustardseeds or any other leguminous or broad leaf vegetation, the same 2 , 4-D chemical will not work because this will kill the wanted plants also along with the unwanted ones. So, in mustard and chickpea (chana or gram) fields, pendimethalin and fluchloralin formulations are used in a prescribed proportion, the scientist says.

Contrary to many farmers' belief that chemical application to destroy weeds is a costly affair, the scientist says that chemical application will work out cheaper compared with the manual weeding of the toxic seeds considering the labour cost involved.

All herbicides are commercially available in the market, he said.However, the destruction of weeds cannot be done at a stretch. Whenever the weeds are found, the herbicides have to be used because what is destroyed in one application is only the weeds that are in the peripheral surface of the land and a lot of seeds will be hidden in the lower layers of the ground. So the treatment has to be done on a regular basis, Gautam says.