The government already has its hand in the food supply with all the farming subsidies it hands out. It can either change the subsidies to match the situation, or get heavily involved into the resource allocation as it has done in wartime.

As a good example, European agriculture is currently threatened because there are no foreign workers in the fields. The German government responded by better connecting unemployed workers to local farms, and by changing the rules to allow some foreign workers to come in.

That's just a hint of what governments are capable of. It pales in comparison to a war economy.