Millions of unsuspecting Indian farmers are spraying fake pesticides onto their fields, contaminating soil, cutting crop yields and putting both food security and human health at risk in the country of 1.25 billion people.

Officials said that the use of spurious pesticides has exacerbated losses in the genetically modified (GM) cotton crop in northern India after an attack by a pest called "whitefly". If unchecked, some of India's roughly $26 billion in annual farm exports could be hit.

Made secretly and given names that sometimes resemble the original, counterfeits account for up to 30% of the $4 billion pesticide market, according to a government-endorsed study. And, they are gaining market share in what is the world's fourth-largest pesticide maker and sixth-biggest exporter.

Influential dealers in small towns peddle high-margin fake products to gullible farmers, in turn hurting established firms like Syngenta, Bayer CropScience, DuPont, BASF, PI Industries, Rallis India and Excel Crop Care.

"We are illiterate farmers; we seek advice from the vendor and just spray on the crop," said Harbans Singh, a farmer in Punjab's Bathinda region, whose three-acre (1.2-hectare) GM cotton crop was damaged by whitefly this year.

"It's a double loss when you see the crop wilting away and your money is spent on pesticides that don't work," he added.

But, S.N. Sushil, who heads India's top pesticide testing laboratory in Faridabad, near Delhi, said farmers panic at the first sight of a pest attack. As a result, they overuse chemicals, reducing their effectiveness and raising costs.

Sushil's team worked overtime after Punjab sent nearly 1,000 samples of suspect pesticides following the whitefly outbreak, finding some to be falsely labelled.

Indian officials tested nearly 50,000 pesticide samples last fiscal year, finding around 3% of them "misbranded", Sushil said.

He added the government was increasing inspections and looking to increase penalties, including jail terms of up to 10 years.

TOXIC RACKET

Lax laws, which punish by revoking licences or imposing short jail terms for offenders, and staffing shortages compromise efforts to track and seize substandard products.

Meanwhile, toxic pesticides that are banned abroad continue to be sold freely in India.

The country still permits the use of "monocrotophos", a pesticide blamed for the death of 23 children in Bihar in 2013 after they ate contaminated free school lunches. That tragedy prompted the Food and Agriculture Organisation (FAO) of the United Nations to advise developing countries to phase out such chemicals.

"Use of excessive pesticides has been a cause for concern for quite some time," said Shyam Khadka, FAO's India representative. "Now if they turn out to be spurious it's a cause for even greater worry."

Chronic exposure to pesticides can lead to depression, a factor in suicides, he said. Pesticides can also cause cancer.

In recent years the European Union and Saudi Arabia temporarily stopped buying some vegetables from India after finding pesticide residues in produce. Indian officials say such cases result from the overuse of chemicals.

RAPID GROWTH IN FAKES

India's fake pesticide industry is expanding at 20% per year while the overall market is growing at 12%.

"We know that a racket is going on," said P.K. Chakrabarty, an assistant director general of Indian Council of Agricultural Research (ICAR). "But, it is only when suspicion arises that people go to inspect."

Karnataka state authorities this month seized large stocks of "Korajen", an illegal copy of DuPont's Coragen used to kill rice pests. Police are investigating similar cases elsewhere, DuPont said.

Punjab has also filed police cases against fake pesticide makers and arrested a senior official at its agriculture university for allowing the sale of counterfeits.

India loses about 4%, or over 10 million tonnes of food output a year due to fake pesticides, said the government-backed study.

"There has been a trend of increasing consumption of (fake) products as against the regular ones," said Manish Panchal of Tata Strategic Management Group (TSMG) that conducted the study.

"All stakeholders should be worried ... it's going to hit food security," he added.