The Central Institute for Cotton Research (CICR), Nagpur, is concerned over the increasing resistance shown by the pink bollworm that affected the cotton crop in Gujarat this season, to the extent of 7-8%. The institute has begun work on a war footing to reach out to cotton growers across the country to ensure that the problem does not persist in the coming season. CICR has also begun to reach out to the government and cotton growers in the north to increase awareness about whitefly management, another issue that had damaged crop in Punjab this season.
According to K R Kranthi, this insect was a serious concern for cotton in India around 30 years ago. “There were very few reports of any major damage by pink bollworm to cotton since 1982 in the country. In 2015, severe damage to bolls by pink bollworm and yield-losses were observed in Bt cotton in many regions of Gujarat and some parts of Andhra Pradesh, Telangana and Maharashtra. What is more worrying is the fact that the worm is chewing up Bollgard-II Bt-cotton which contains two genes (cry1Ac+cry2Ab) that were supposed to be highly effective in controlling the pest,” he said.
Studies conducted by ICAR and CICR over the past two years clearly showed that the pink bollworm developed resistance to two Cry toxins deployed in Bollgard-II. The institute is attempting to find out why the worm has returned after 30 years to trouble cotton again. “Our approximate estimates indicate that Gujarat may have lost 7-8% of its cotton to the pink bollworm this year. Of greater concern is the fact that the farmer would get a lower price for the second and third picked cotton because of the poor quality. At a time when the market prices are low, this could compound the stress. Surveys conducted by ICAR and CICR showed that pink bollworms were also surviving on Bollgard-II not only in Gujarat but also in parts of Andhra Pradesh, Telangana and Maharashtra,” he said.
The problem persists in areas where the cotton crop is being extended beyond 180 days, sometimes extending it all through the year. The pink bollworm generally arrives with the onset of winter and continues to survive on the crop as long as flowers and bolls are available. Long-duration cotton allows the pest to thrive for a longer continued period in multiple cycles, thereby affecting the subsequent cotton crop. Reports of pink bollworm damage in BG-II were received in July 2015. Farmers complained of pink bollworm in Amreli, Dhari, Jambusar in Bharuch, Karjan, Shinor-Padara and Daboi in Vadodara during July 2015. Pink bollworm damage was reported from Garaidar Taluka of Bhavnagar in August 2015. CICR deputed a team of scientists to survey the regions and collect samples for analysis. The team reported extensive occurrence of symptoms that are caused due to pink bollworm damage. “Insect resistance to toxins is a signal that is dangerous to ignore. The problem can only get worse over the ensuing years, if left unattended” Kranthi cautioned. The simplest and most potent way to overcome the problem is to take up timely sowing and cultivate early maturing short duration varieties of about 150 days duration and ensure a gap of at least five-six months between two crops so that the worm does not recur in the ensuing season.
CICR has been reaching out to state departments and universities to talk about the resistance factor and has been sending voice mail weekly advisories to 1,80,000 farmers across India and 11,893 farmers in Gujarat on this issue.