A pest said to be every bit as damaging as late blight and nematodes is on the move around Moses Lake, WA, and Hermiston, OR. Potato tuber moths are inflicting crop loss that extends from the field and into storages and processing applications.
In the larval form, potato tuber moths are a leaf miner. They live inside the leaves and stems of potatoes preferring green vines to tubers. Because they carryout early life stages "inside" the plant, they are particularly difficult to control.
When the vines are killed, the larvae move into the tubers where the greatest damage is inflicted. They burrow mostly just under the surface, but in some cases deeper into the tuber.
Unlike wireworms which leave clean tunnels, the larvae excrete waste in their tunnels. This presents an extreme quality issue for both fresh and processing potatoes.
According to Mel Martin of Simplot's Food Group, potatoes have already been rejected for processing because of tuber worm infestation. The biggest problem is not being able to see surface damage to potatoes when the larvae enter the tuber.
Processors are very concerned because there isn't a good way to discover the damage in the processing line. Sampling methods and efforts have increased and potatoes will be inspected more so than in the past.