The immediate cause of this food spike was the worst drought in Russia and the Black Sea region for 130 years, lasting long enough to damage winter planting as well as the summer harvest. Russia imposed an export ban on grains. This was compounded by late rains in Canada, Nina disruptions in Argentina, and a series of acreage downgrades in the US. The world’s stocks-to-use ratio for corn is nearing a 30-year low of 12.8pc, according to Rabobank.