ADM’s $8 Billion Wipeout Needs More Than Nutrition for Road Back

It took just one day for Archer-Daniels-Midland Co. to lose more than $8 billion in value following news of an investigation into its accounting practices earlier this year. Bouncing back will take a lot longer.

The storied agricultural commodities trader, which historically dubbed itself the “supermarket to the world,” has spent billions to grow its nutrition unit, the business that makes pet food and veggie burgers that’s now under scrutiny. But the strategy to diversify beyond corn, wheat and soybean trading — ADM’s staples — has faltered, with no obvious alternative in place.

To make matters worse, the cycle for ...