Texan tatties assailed by new illness

Texan potatoes are under attack from a new mystery ailment.

‘Zebra chip’, named after the dark stripes it leaves in the flesh of raw potatoes, is not harmful to human health, but causes serious and expensive reductions in crop yields and quality.

Symptoms are especially pronounced when potatoes are sliced and fried to make potato chips. Frying plants are therefore rejecting entire loads of affected potatoes.

"Zebra chip defies typical diagnostic techniques that would point to a known bacteria or a virus causing this disorder, so we suspect it's something more complex," says Dr. John Goolsby, a research entomologist at the U.S. Department of Agriculture.

Goolsby suspects whatever is causing Zebra chip is transmitted by insects.

"It appears to be vectored by an insect because when we place a cage over potato plants to exclude insects, the plants don't get Zebra chip," he said. "And of the insects we've evaluated, we believe it is vectored by the potato psyllid, an insect native to this part of the world. But we're not sure what the pathogen is.”