The worst locust infestation in more than 50 years is threatening Argentina.

(The National Animal Health and Agri-food Quality Service of Argentina (Senasa))

Locusts are on the cusp of devastating parts of Argentina, as mild temperatures in the region have helped them to flourish, much to the chagrin of farmers, who fear they will obliteratecrops and grassland.

The hungry swarms of voracious grasshoppers now cover an "area of northern Argentina about the size of Delaware," The New York Times .The favorable weather conditions ("mild and rainy winter"), combined with insufficient control efforts,have allowed the insect to thrive.

"In order to have the locust outbreak of this magnitude, there must have been several years of population growth that went relatively unchecked," Hojun Song,entomology professor at Texas A&M University, said."After several generations of no locust problem, there must have been a continuous reduction of infrastructure and personnel for locust control."

"The locust species causing havoc in Argentina is the South American locust, Schistocerca cancellata," Alexandre Latchininsky, University of Wyoming entomologist, told weather.com in an email. "Its breeding areas are concentrated in the northern part of Argentina (La Rioja, Catamarca), mostly between 18 and 35 degrees south, in dry or semi-desert areas ... it can attack a very wide variety of crops and wild plants. The main crops damaged are beans, citrus, cotton, maize, cereals, potatoes, sugar cane etc. Many trees can be attacked, too. So the economic importance is very high."

Latchininsky said that climate change can influence the species in several ways.

"First, if the rains become more abundant in its breeding areas, this would trigger an outbreak. (When it is dry, only one annual generation instead of three develops)," he said. "Second, higher temperatures may allow the locust to occupy more areas to the south and expand its range."

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"Since the wet winter, it seems to have been near average for precipitation,"said Jonathan Erdman, senior meteorologist for weather.com. "However, according to NOAA's global state of the climate report for 2015,it appears to have been the record warmest year in far northwest Argentina. So the warmth may have contributed to the locust swarm."

Latchininsky noted that the the conditions allowed the locusts to quickly populate. They then fly south, and "invade many Argentinean provinces; there were cases in the past when 15 out of 22 provinces were invaded," he said, adding "The locust has very high reproductive capacity: One female can lay several egg pods with about 100 eggs in each, so the population may increase very quickly."

Senasa, the government’s agricultural agency, issued warnings to farmers to report the infestations to the authorities. The agency has found success in being able to contain multiple swarms with help from increased pesticide deployment by provincial and municipal governments, it also stated in press releases.

However, Amir Ayali, a professor of Zoology at Tel Aviv University who was a consultant during the locust outbreak in Israel in 2013, told weather.com that its hard to know if pesticide spraying will be an effective solution in the long run.

"As very often happens with locusts, one never knows in retrospective how much of the final success in combating the locusts can be attributed to the massive spraying, and how much is simply due to the natural behavioral migration cycle," Ayali said.

"Considering all factors, I believe that Argentina is in it for a long haul," Song added.

Pablo Cortese, Director of Surveillance and Monitoring of the National Direction of Plant Protection from Senasa, told weather.com that damage from the locusts has largely been isolated outside of farmland.

"Concern exists, we are alert, but the reality is that we have not recorded or reported so far in crop damage," Cortese said. "It's noteworthy that most of the current work area are occupied mostly by mountain / natural field."

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