BUENOS AIRES — Farmers and fumigators in Argentina are running out of time as they scramble to control the country’s worst plague of locusts in more than half a century, officials warned on Monday.
The provincial authorities and Senasa, the government’s agricultural inspection agency, have intensified their efforts to exterminate swarms of the insects in the dry forests of northern Argentina. But their attempts might not be enough to prevent the locusts from developing into a flying throng in the coming days — when they will then threaten to devour crops like sunflowers and cotton, and grasslands for cattle grazing.
“It’s the worst explosion in the last 60 years,” Diego Quiroga, the agriculture agency’s chief of vegetative protection, said in a telephone interview. “It’s impossible to eradicate; the plague has already established itself. We’re just acting to make sure it’s the smallest it can be and does the least damage possible.”
Small pockets of locusts, which first appeared last June, at the start of winter in the Southern Hemisphere, have spread across an area of northern Argentina about the size of Delaware. The mild and rainy winter here created comfortable breeding conditions for the locusts; their surge outpaced the ability of the authorities to control the spread of the insects.
Farmers last year reported locust clouds that were more than four miles long and nearly two miles high, said Juan Pablo Karnatz, a representative for the Province of Santiago del Estero at the Rural Confederations of Argentina, which represents more than 100,000 farmers here.
In the past five years, Senasa, the agricultural agency, has seen an increase in the numbers of insects that can destroy crops — like fruit flies that threaten citrus groves — as a result of warmer, wetter winters.
Mr. Quiroga pointed to a warning last November by the Food and Agriculture Organization, a United Nations agency, which said climate change would contribute to locust plagues in Africa. “There is clearly an impact in our country, too,” he said. “We are definitely being affected.”
Many farmers here blame the coming plague on the previous government of former President Cristina Fernández de Kirchner, saying officials failed to take last year’s warnings seriously enough. There is no study yet that shows climate change has led to the increase in locust populations, said Paola Carrizo, a professor of agronomy at the University of Buenos Aires, explaining that a more likely cause was insufficient pest control by Senasa.
The specter of locusts haunts Argentina’s farmers, who for almost 200 years have resorted to rustic methods like bonfires to drive away menacing swarms. A government program to combat locusts, set up in 1891 under President Carlos Pellegrini, is believed to be one of Argentina’s oldest agricultural policies.
After years relatively free from locusts, farmers are again bracing themselves for the worst. Senasa has set up a hotline to report sightings of the insects. And in meetings this month to coordinate a response to the plague, officials in Argentina have been emphasizing the havoc locusts can wreak by digging out sepia-toned photographs of past plagues.
Fumigators equipped with backpack sprayers intensified their efforts last week. They have extinguished pockets of young locusts, which cannot yet fly, only hop, in 66 locations in northern provinces of Argentina. The dry forests there are largely impenetrable, however, so it is unclear how many other pockets have gone undiscovered.
In 10 days, the locusts are expected to grow to about two inches and mature into voracious flying swarms in search of food. Once that happens, combating the plague would be a more complex operation, Mr. Quiroga said, requiring fumigating aircraft to poison the swarms.
“We don’t know exactly where we’re at,” said Mr. Karnatz, the farmers’ representative, who has been involved in coordinating a response to the plague. “We may have contained some pockets, but it’s not a definitive victory.”
He warned, “If they fly, it could be disastrous.”