The two biggest western shippers of Russian grain, Cargill Inc. and Viterra will halt purchases for export in a shift that will give local firms more control over shipments. Glencore-backed Viterra’s management team in Russia plans to create an independent Russian grain exporter once the company ceases export activities in the country, Cargill will take a further step back from the Russian market by no longer handling the top wheat supplier’s grain at its export terminal from July, although its shipping unit will continue to carry grain from the country’s ports.