36 POTATO GROWER | MARCH 2024
DIGGIN' IN
ZEBRA CHIP | Scott Elliott
Researchers Try To Pinpoint A
Moving Target
Zebra chip is a disease of potatoes. It won't hurt humans
who eat it, but its bitter taste – and the fact that it kills host
plants – makes it an economic nightmare for potato farmers.
Scientists understand the disease fairly well, and know that
the pathogen that causes zebra chip is spread to plants by the
sap-sucking potato psyllid. Potato psyllids resemble small cica-
das. They are small, black insects with white stripes on their
heads and mid-section and straw-like mouthparts that they
insert into the plant to drink its sap.
While the pathogen can alter the insect behavior slightly, its
biggest impact comes from its transmission to host plants. Af-
ter a psyllid feeds on a plant that is affected by the disease, the
pathogen is passed to the potato through the psyllid's saliva
during the feeding process. It doesn't take long for an infected
potato plant to deteriorate and die.
"Growers use insecticide applications to reduce populations
of the potato psyllids," said Rodney Cooper, research leader
at the Agricultural Research Service's (ARS) Temperate Tree
Fruit and Vegetable Research unit (TTFVRU) in Wapato,
WA. "The use of insecticides is challenging because potato
Insect that transmits potato pathogen plays hide-and-seek
Potato infected with zebra chip. Photo by Kylie Swisher Grimm, ARS
