Too much too often: Antibiotics in Indian crops can make them ineffective

Antibiotics are indiscriminately used on food crops in several parts of the country, adding to the burden of antibiotic resistance    

By Bhavya Khullar, Rajeshwari Sinha, Amit Khurana
Published: Wednesday 20 November 2019
Antibiotics in agriculture. Photo: Getty Images

Dharampal Singh just cannot stop admiring the cauliflowers glistening with beads of dew on his farm near the Yamuna banks in Delhi. Next to the plot, rows of radishes, spinach, fenugreek and bottle gourds lie shining in the morning sun.

“These untainted vegetables fetch me a premium in the market,” says Singh, as he prepares to spray a white powder on the crop. “Spraying this at regular intervals ensures that my plants stay healthy and green until harvest.”

The powder, which Singh has been using so generously for last few decades, is streptocycline — a mixture of two antibiotics used for treating life-threatening bacterial infections in humans. In fact, the World Health Organization (WHO) recognises the antibiotics — streptomycin and tetracycline — as “critically” and “highly” important for human medicine.

Streptomycin is used in humans for “previously treated tuberculosis” that accounts for over 10 per cent of the estimated 2.7 million TB incidences in India. It is also used to treat multidrug-resistant TB and certain cases of TB meningitis. Resistance to streptomycin is already high and its large-scale non-human use could add to the problem.

An antibiotic (doxycycline) belonging to the class of tetracycline is the drug of choice for treating rickettsial, which gets transmitted by insects and is a covert re-emerging infection in India.

The indiscriminate use of such crucial antibiotics is worrying as the practice may lead to the development and spread of antimicrobial resistance (AMR), already a pressing concern worldwide; at least 10 million people are likely to die of AMR every year by 2050. When used in crops, unspent antibiotics find their way into the surrounding environment.

Microorganisms exposed to this increasing load of antibiotics in soil and water can develop resistance to it. The resistance can spread to other bacteria through transfer of genetic material. When humans or animals get infected by such resistant microorganisms, their treatment becomes difficult as well as expensive.

There is a possibility that traces of antibiotics remain in edible parts of the plant long after streptocycline is sprayed, affecting human health or making them resistant to the antibiotics.

To gauge the extent of the use of antibiotics on crops in the country, researchers at Delhi-based Centre for Science and Environment (CSE) visited several farms near the banks of the Yamuna in Delhi as well as in Fazilka district of Punjab and Hisar district of Haryana. They also spoke to fruit growers in Maharashtra, Andhra Pradesh and Himachal Pradesh. Just like Singh, none of the farmers knew that streptocycline is a combination of antibiotics, and were routinely using it as any other pesticide.

The Central Insecticide Board and Registration Committee (CIBRC), the country’s apex body that approves the use of pesticides, says streptocycline should be used when plants develop bacterial infections like leaf blight, fire blight, citrus canker, rotting of fruits and stems, leaf spots and soft rots (yellowing and drooping of leaves).

But CSE researchers found the farmers using it even in the absence of disease symptoms. Worse, there is little monitoring on how it is being applied.

“We use streptocycline to avoid infections and subsequent crop loss,” says Satpal, a vegetable grower in Delhi. He mixes streptocycline with a host of other medicines and sprays on the plants twice a week throughout the crop season. “This way plants do not contract jhulsa rog (yellowing or drying),” he says.

In Hisar, vegetable grower Ram Avtar Saini vouches by the efficacy of streptocycline: “It’s the only medicine that can save bottle gourd from galav rog (rot).” In the first week of November, when CSE spoke to him, he had procured 30 packets of streptocycline, each weighing 6 grammes.

CSE researchers also found that farmers were using streptoycline with little regard to the recommendations by CIBRC. For instance, CIBRC recommends using streptocycline only on two fruits — apples and citrus. But in Maharashtra’s Akola district, Rahul Asbe says he has already sprayed streptoycline five times on his pomegranate crop: “Two more rounds of spraying will be done before the harvest in December.”

Farmers in the Yamuna bank admit to be routinely using streptocycline on cauliflower, cabbage, spinach, bottle gourd, apple gourd, cucumber, mustard, brinjal, fenugreek, radish and coriander, whereas CIBRC recommends its use on beans, potatoes and tomatoes.

There are also grave anomalies in the way streptocycline is being used. Most farmers say they mix fungicides with streptocycline before spraying as they are unable to distinguish fungal or bacterial diseases. “Modes of action of antibiotics and fungicides are different, and there is no evidence to suggest that streptocycline enhances the action of other chemicals,” says Dinesh Singh, principal scientist at the Indian Agricultural Research Institute (IARI), New Delhi.

CIBRC recommends specific dosages of streptocycline for different crops. For example, a solution of 25-50 parts per million (ppm) is recommended for apples in case of fire blight; 100-150 ppm for beans with halo blight; and 40-100 ppm for tomatoes with bacterial leaf spots. But farmers rarely follow the recommendations.

CSE researchers found that farmers usually dissolve an entire packet of streptocycline in different volumes of water, depending on the capacity of the tank of the air-blast sprayer with them. The resulting concentration is three to four times higher than what is recommended.

To understand the reason for such routine violation of CIBRC recommendations, CSE looked at a few state agriculture institutes that run Krishi Vigyan Kendras (KVK) to help farmers tackle agriculture-related problems. A glance at their websites shows many KVKs recommend streptocycline on crops not listed for use by CIBRC.

Explaining the reason, a senior official with the Dr YSR Horticultural University at Tadepalligudem, Andhra Pradesh, says: “University recommendations are based on guidelines of the Indian Council of Agricultural Research (ICAR). These may be different from CIBRC but are based on scientific evidence.”

Another scientist at the Dr YS Parmar University of Horticulture and Forestry at Nauni, Himachal Pradesh, says KVK recommendations are based on scientific studies and regional or local requirements. “If blight appears on pomegranate, streptocycline will have to be used despite CIBRC not recommending it,” he adds.

But CSE researchers’ discussions with farmers show otherwise. In the absence of a robust extension machinery, the farmers’ actions appear to be influenced by what pesticide dealers say. “I do what Shyam suggests,” says Ram Avtar, referring to the local pesticide dealer. “We have not met any government official in years. Shyam and company doctors (representatives selling streptocycline) are the only help we have,” he adds.

In Fazilka, Vinod Kumar, who grows orange, lemon and kinnow on his 12 hectare farm, also cites lack of support from extension officers as a reason for seeking guidance from pesticide dealers. When CSE contacted pesticide dealers, they said they prescribe dosages as recommended by companies or the government.

“But only 10 per cent of the farmers give the right dose,” says Arvind Kumar Patel, secretary of the Agro-Input Dealers Association, Pune. Commenting on the effectiveness of the extension machinery, Beant Singh, chief agricultural officer of Fazilka, says: “There is a provision to fine and punish those who violate norms and sell unapproved chemical inputs. Agriculture officers regularly inspect pesticide shops to prevent such sale.”

However, a senior official with Maharashtra’s state agriculture department in Amravati admits that lack of staff and added responsibilities are reasons for weak enforcement on the ground. “Existing insecticide officers are assigned multiple tasks on issues of soil and water, natural calamities and sometimes even insurance-related matters. There is not enough time for effective enforcement on the ground,” he says.

Surprisingly, key drug regulator of the country, the Central Drugs Standard Control Organisation (CDSCO), does not have any role in regulating antibiotics used on crops. Highlighting the definition of “drug” as stated in the Drugs and Cosmetics Act (D&C Act), 1940, a senior CDSCO official says, “Antibiotics meant for plants or crops do not fall within the purview of the present drug laws. Hence, cdsco has no jurisdiction over antibiotics sold for treating plant diseases.”

When asked about the role of state drug regulatory bodies, a senior official at the Food and Drugs Control Administration in Gujarat says, “State drug authority cannot exercise any control over companies that manufacture or sell antibiotics for use in crops as they manufacture and sell the product as pesticides.” 

To add to the above, CIBRC has wrongly registered streptocycline as a fungicide. When enquired, a CIBRC official on condition of anonymity, said: “The classification depends on what companies mention on their application forms and the supporting data they submit during registration. Unless this is challenged with data, CIBRC cannot reclassify the chemicals into a new category.”

The justification seems weak as companies should align their actions with laws set by regulatory authorities and not vice versa. CIBRC also does not provide any withdrawal period for antibiotics, which ensures that chances of antibiotic residues present in food are reduced.

To make matters worse, streptocycline is assigned low toxicity, meaning no special precaution needs to be taken for its use. But this labelling does not consider health hazards like amr which could arise due to exposure of farmers to the antibiotics they spray.

Laboratory-based studies have also shown the presence of antibiotic residues in crops at a later stage. But the Food Safety and Standards Authority of Indian (FSSAI) does not provide any separate tolerance limit for streptocycline in food products. A national record of antibiotics being produced or consumed as pesticides for crops is also lacking.

Ironically, when CSE had filed an application under Right to Information with the Directorate of Plant Protection, Quarantine and Storage (PPQS) to enquire about annual consumption of streptocycline used for crops, it disposed of the request in May 2018, saying it does not have the information.

Though the data was made available on its website a few months later, its veracity is doubtful. For instance, total consumption of streptocycline in the country during the two years between 2014 and 2016 is 0.21 tonnes, while it is 25 tonnes for 2016-17 alone. Data available on the website of Hindustan Antibiotics Ltd (HAL), which manufactures brand “Streptocycline” in India, shows it has capacity to produce 18 million packages of 6 g each.

This means it can produce 108 tonnes of streptocycline a year. Even if 50 per cent of it is used in India, consumption would be close to 50 tonnes. CSE researchers found other brands of streptocycline being sold, such as unimycin, tagmycin, streptosac, agromycin and cristocyclin.

The presence of residual antibiotics in the environment after their spraying on crops and their linkages to AMR remains a matter of concern across countries where antibiotics are used on crops. But some have found ways to regulate its use. For instance, streptomycin and oxytetracycline (which belongs to the class of tetracycline) are not approved for use in the European Union.

These are allowed to be used only under exceptional circumstances, such as in case of a disease outbreak that cannot be contained by other means. A recently released report by the Food and Agriculture Organization and who recognises the link between antimicrobials used in crops and AMR.

The report recommends integrated pest management as an effective approach to limit the use of antimicrobials in crops.

Pesticides are agro-chemicals used to protect plants from pest attacks. Antibiotics, on the other hand, are drugs meant for treatment of bacterial diseases in humans. They should not be used as pesticides and be used under expert supervision only after a bacterial disease has been diagnosed in a crop.

All the other uses of antibiotics should be considered as misuse and phased out. To contain AMR from agriculture sector, there is a need for multiple stakeholders to come forward and take the following urgent steps.

CDSCO needs to consider amending the D&C Act to bring antibiotics used in plants as “drugs” under its purview. Necessary law, such as Schedule H for antibiotics, should be introduced to ensure that no antibiotic is sold for use in agriculture without prescription. CIBRC should reclassify streptocycline as an antibiotic and ensure that it is not sold as fungicide or pesticide.

It should also set withdrawal periods for stryptocycline, and revisit its toxicity labelling taking into account AMR. The Ministry of Agriculture and Farmer’s Welfare (MoAFW) should work towards strengthening the extension machinery and creating awareness among farmers, dealers and extension officers towards limiting antibiotic misuse in crops.

Just like antibiotics are prescribed for humans and animals, MoAFW should introduce the concept of “plant health experts” and train them to help farmers with disease diagnosis and use of inputs.

Alongside, ICAR should engage in research and development of effective and low-cost alternatives to antibiotics. 

PPQS should carry out surveillance of antibiotic used in crops and make data available in the public domain. 

FSSAI should come out with separate tolerance limits for streptocycline in food and conduct surveillance for monitoring antibiotic residues in plant-derived food

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