New plagues of locusts threaten South American crops

In May, farmers in Paraguay, Argentina, Uruguay, and Brazil went on red alert over reports of locusts roving across the southeastern portion of the continent, demolishing crops as they go. However, despite traveling long distances over months until dissipating, the swarms did not reach Brazil, causing losses only in Paraguay and Argentina. But the danger has reared its head once more.

On Friday, Argentina’s Food Safety and Quality Service (Senasa) sounded the alarm when it found another swarm of locusts close to the towns of Campo Viera and Itacaruaré, in the northeastern Argentinian province of Misiones, bordering the Brazilian towns of Rincão Vermelho and Porto Xavier on the banks of the Uruguay River.

First indications show that the locust species of this new swarm is different to that seen in August. This is crucial, as the Chromacris speciosa locust — the reason for these renewed alerts — is not accustomed to making long flights, suggesting the problem will be largely contained.

Experts from Brazil and Argentina are monitoring the locust clouds and have asked farmers to alert the authorities of any changes they observe. So far, the insects have been seen on three farms in Campo Viera and one in Itacaruaré,...