Meant to eradicate locusts, pesticides affect soil, crops
The Food and Agriculture Organisation (FAO) of the United Nations said on Friday that it may declare the locust invasion a plague if it takes a turn for the worse after breeding by the voracious, crop-crunching insects in India, Pakistan and West Africa.
FAO now categorises the locust invasion that has reached India as an “upsurge”. Swarms of desert locusts have chomped through vegetation and crops across farm lands in Punjab, Madhya Pradesh, Maharashtra, Gujarat, Uttar Pradesh and Chhattisgarh.
The Locust Warning Organisation (LWO) sprayed Malathion 96 and Chlorpyrifos, both organophosphate pesticides, to control the locust swarms across states. Both are extremely toxic and high level of exposure to the pesticides may cause nausea, dizziness and even death. They can also impact soil fertility by altering the ecological balance.
“We have conducted control operations in 47,000 ha in Rajasthan, Gujarat, Rajasthan and Madhya Pradesh by spraying pesticides,” said KL Gurjar, deputy director of the LWO. A swarm near Jhansi in UP has scattered. Gurjar said there is no clear indications the locusts will head towards Delhi.
FAO, saying it may declare a plague of locusts, cautioned that farmers shouldn’t try to control the swarms.
“Unfortunately, spraying of chemical insecticides is the only effective method when desert locusts are in such large numbers. There are bio-pesticides which are safe ways of controlling them, but may not be as effective. FAO doesn’t encourage control of desert locusts by farmers. State or federal teams that are trained in locust invasion management should do it with safety equipment,” said Keith Cressman, senior locust forecasting officer at FAO, at a webinar organised by the Centre for Science and Environment on Friday.
One of the options with farmers is to dig trenches around their farms to prevent hoppers from entering. Noise can scatter locusts, but they prevent focused control operations by the authorities as the swarms move in different directions.
Cressman said the current severe locust invasion was linked to climate change-induced aberrations in rainfall. “There was good breeding in India last year, the monsoon was protracted which allowed further increase in locust populations. The drying vegetation in south-west Pakistan also led to them reaching India a month in advance,” he said. India was alerted by FAO last year about the possibility of waves of invasions.
The desert locusts were expected to remain limited to its habitat in Rajasthan, but the swarms scattered to Madhya Pradesh, Uttar Pradesh and Maharashtra because of the strong north-westerly winds following cyclone Amphan, which struck West Bengal and Odisha on May 20.
“Except for Malathion 96, the rest that they are spraying are highly poisonous pesticides. They are red-labelled. They are meant for locust control in desert areas which are largely uninhabited. But the same pesticides are being sprayed on in areas with habitation and with water bodies. These pesticides will drift and residue will remain. They will definitely disturb the ecological balance of the area and kill natural enemies—pests which can counter other crop pests. So, we can expect outbreak of other pests,” said GV Ramanjaneyulu, executive director at the Centre for Sustainable Agriculture.
“Desert locusts don’t multiply in non-desert areas so there is no point in spraying toxic pesticides in such large quantities in other states. They have a short life cycle and will die in due course. Government must consider biocontrol agents,” he added.
With the onset of monsoon rains, the locusts will come back to their summer breeding sites in the desert along the India-Pakistan border. “They will be flying back and forth with the winds till monsoon arrives,” Cressman said.
The other forecast that FAO has made is that with the south-west monsoon winds, desert locusts that bred in the Horn of Africa will travel to Rajasthan across the Indian Ocean in June.
“Spraying of insecticides is compounding environmental problems in the Horn of Africa. We do not have wherewithal to undertake these measures at the scale required, we need aircraft to spray, expertise to spray. Biotechnological interventions should be considered…locust invasions are an existential challenge if they are allowed...in the coming years,” Richard Mark Mbaram, technical adviser to the Nigerian ministry of agriculture, said