Glyphosate

In News: The Union Agriculture Ministry has restricted the use of glyphosate, a widely used herbicide.

• This comes even as the Supreme Court is about to take up a plea seeking a ban on all herbicide-tolerant crops, including transgenic hybrid mustard and cotton.

What is glyphosate?

• It is a herbicide used to kill weeds — undesirable plants that compete with crops for nutrients, water and sunlight.
• Glyphosate is a broad-spectrum herbicide that can control a wide range of weeds, whether broadleaf or grassy.
• It is also non-selective, killing most plants.
• When applied to their leaves, it inhibits the production of a protein ‘5-enolpyruvylshikimate-3-phosphate synthase (EPSPS)’.
• This enzyme, produced only by plants and microorganisms, synthesises aromatic amino acids that are necessary for their growth.

Use in India

• There are nine glyphosate-based formulations containing different concentrations of the chemical registered for use under the Insecticides Act, 1968
• These are approved largely for weed control in tea gardens and non-crop areas such as railway tracks or playgrounds.
• Farmers also apply glyphosate on irrigation channels and bunds to clear these of weeds, making it easier for water to flow and to walk through them.

Concerns

• In general, though, the scope for glyphosate use is limited for the very reason that it is non-selective.
• Designed to kill all plants coming into contact with it, the chemical cannot ordinarily distinguish between crop and weed.
• Hence, it can be used in tea or rubber plantations, but not in fields where the crops and weeds are at almost the same level.

What exactly has the government now done?

• The Ministry issued a notification stating that “the use of glyphosate involves health hazards and risk to human beings and animals”. It has, however, not banned and only “restricted” its use.
• The spraying of glyphosate and its derivatives shall henceforth only be permitted through “pest control operators”.

Why has this been done?

• Glyphosate application has increased only with the advent of genetic modification (GM) or transgenic technology.
• In this case, it has involved incorporating a ‘cp4-epsps’ gene, isolated from a soil bacterium Agrobacterium tumefaciens, into crop plants such as cotton, maize and soyabean.
• This alien gene codes for a protein that does not allow glyphosate to bind with the EPSPS enzyme.
• The GM crop can, therefore, “tolerate” the spraying of the herbicide, which then kills only the weeds.
• In 2019 alone, some 81.5 million hectares were planted worldwide with herbicide-tolerant (HT) GM crops. The global glyphosate market is annually worth $9.3 billion, with over 45 per cent of use on account of GM crops

How valid are the health concerns over glyphosate?

• The World Health Organisation’s International Agency for Research on Cancer (IARC), in March 2015, classified glyphosate as “probably carcinogenic to humans”
• The US Environmental Protection Agency, on the other hand, has held that there are “no risks of concern to human health from current uses of glyphosate” and “no evidence” of it causing cancer. Its findings are based on “a significantly more extensive and relevant dataset

For now, what’s not in doubt is the demand for herbicides and crops that can withstand their application among Indian farmers.

The Union Environment Ministry’s Genetic Engineering Appraisal Committee (GEAC), recently recommended the commercial release of GM hybrid mustard. This crop can also tolerate the spraying of glufosinate ammonium, a non-selective herbicide similar to glyphosate.

Must Read: GM Crops and their regulation

Source: Indian Express

Previous Year Question

Q.1) Triclosan considered harmful when exposed to high levels for a long time, is most likely present in which of the following? (2021)

1. Food preservatives
2. Fruit-ripening substances
3. Reused plastic containers
4. Toiletries