As the coronavirus pandemic penetrates more deeply into global supply chains, prices for key staples are starting to soar in some parts of the world.

Rice and wheat — crops that account for about a third of the world’s calories — have been making rapid climbs in spot and futures markets. For countries that rely on imports, this is creating an added financial burden just as the pandemic shatters their economies and erodes their purchasing power. In Nigeria, for example, the cost of rice in retail markets soared by more than 30 percent in the last four days of March alone.

It’s unclear what the biggest drivers were for the retail prices, whether it was a trickle-down effect from grain futures or local logistical choke points or panic buying, or a combination.