NAGPUR: Once again pink bollworm pest, dreaded by cotton growers, has appeared in the fields. This bolsters the theory that the insect has developed resistance against genetically modified Bt cotton seeds in large pockets of the country.

Unseasonal rains have led to favourable climatic conditions for the pest to breed. This is supported by the delayed cotton crop standing in the fields.

It’s in initial stage, however, with no major threat seen at present, say authorities, including those at Central Institute of Cotton Research (CICR), the premier research agency of the government based at Nagpur.

Farmers use the BGII cotton seed produced using the technology developed by US biotech giant Monsanto. A Monsanto spokesperson, however, declined to comment on the issue.

Reports by CICR show presence of the pest in cotton fields of Maharashtra, Gujarat, Karnataka, Telangana and Madhya Pradesh. Last year, better pest management had helped curb the infestation to a considerable extent. There was a major attack in 2017, followed by high pesticide spraying which also led to the deaths of farm hands due to accidental inhalation poisoning by chemicals.

Experts admit that though the situation may not be as bad as 2017, infestation is certainly more than last year. Yet, it has not reached the economic threshold limit (ETL) in majority of the areas. ETL is the threshold level after which infestation can lead to tangible loss in output

Vijay Waghmare, director of CICR, confirmed the pest was found in some states. He told TOI that it is already confirmed that the pest has developed resistance in large areas. Pink bollworm can only be controlled by integrated pest management practices rather than Bt technology alone in many pockets, he said.

Another reason for the attack is that the cotton is already 120 days old, after which the Bt gene expression that provides resistance against bollworm weakens. Waghmare said it is too early to panic. It was also noted that bollworm’s resistance against the pest is not uniform. For example, it’s more in areas like Yavatmal, where cotton is a major crop, as compared to Nagpur, where area under the crop is relatively less.

An advisory issued by Panjabrao Krishi Vidyapeeth (PDKV), agriculture university at Akola, mentions that over 1,000 insects were found in the four pheromone traps kept in experimental farms of the institute. These are like honey traps, where the insect is attracted using the female’s scent.

Upendra Kulkarni, associate professor (etymology) at PDKV, said even as resistance to Bt gene cannot be ruled out, even climatic conditions have a major role to play. Farmers too extend the crop beyond December, which creates a favourable condition for the pest, he said.

