The role of agro-scientists in pest management is crucial. They ensure the health of crops while equally caring for the environment. In recent times, scientists from the National Centre for Integrated Pest Management (NCIPM) and Indian Council of Agricultural Research (ICAR) are working on implementing safer alternatives to harmful substances used in pest eradication. Their notable work involves substituting methyl bromide with phosphine as a fumigation agent.
The Role of Methyl Bromide
Methyl bromide, used extensively for fumigation at ports, is effective in eradicating various insect pests. Despite its effectiveness, it poses an environmental threat due to its ozone-depleting nature.
As a signatory to the Montreal Protocol, India has pledged to phase out methyl bromide and other similar substances by 2015. However, Indian ports continue to use this fumigant for treating imported cereals and pulses. The negative impact of methyl bromide is expanded by the fact that it has 60 times more ozone-depleting potential than refrigerant chlorofluorocarbons, which are now globally phased out.
It’s worth noting that 95% of the world has phased out the use of methyl bromide, except India and a few South East Asian countries. The Indian government has been penalizing exporters who ship food products without treating them with methyl bromide, causing several contentions in bilateral trade deals.
Transition to Phosphine
India prohibits the use of methyl bromide in domestic warehouses due to its residual properties, replacing it with phosphine. Because grains in the warehouse need to be fumigated every three months, phosphine’s no-residue feature is preferred over methyl bromide.
However, due to its fast-acting properties, methyl bromide is still chosen over phosphine as a quarantine pest fumigant, capable of eliminating pests like grain borers, beetles, and weevils in less than 24 hours, while phosphine takes almost five days.
Ozone-Depleting Substances
Ozone-depleting substances (ODS) are synthetic gases that cause the ozone layer’s destruction once they reach the stratosphere or upper atmosphere. The ozone layer protects Earth from the sun’s harmful ultraviolet radiation, which can cause skin cancer, cataracts, affect plant growth, and damage the marine environment.
Table: Common Ozone-Depleting Substances
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| Substance | Common Usage |
|---|---|
| Chlorofluorocarbons (CFCs) | Refrigerants in air conditioners and refrigerators |
| Hydrochlorofluorocarbons (HCFCs) | Refrigerants in home and vehicle air conditioners |
| Halons | Components in electrical equipment |
| Methyl bromide | Fumigants, solvents for cleaning |
| Carbon tetrachloride/Methyl chloroform | Industrial solvents, aerosol spray propellants |
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Phosphine as an Effective Replacement
Scientists from the NCIPM and ICAR have conducted experiments in four different agro-climatic locations to test phosphine’s effectiveness as a methyl bromide replacement. Phosphine is 100% effective against pests as a fumigant in gaseous form. It is generally produced using aluminium phosphate as a substrate. Phosphine could potentially be as effective as methyl bromide in killing insect pests and could be used as a quarantine fumigant at ports, providing a more environmentally friendly solution.
