Something is causing my potato crops to be affected by zebra
chip. My tubers have black, zebra-like stripes in their flesh
and the outcome for me has been decreased sales. Why is
this happening, and what can I do to eliminate this problem?
— Annoyed in Gaines County, Texas
Those zebra-like stripes are indeed signs of zebra chip, caused by
bacterium that is vectored by potato psyllids. While this issue has
been limited to only a few areas of the southern U.S. in the past,
zebra chip was found in some areas of the Pacific Northwest in
2011. The key to sustaining a healthy crop will be to understand
the cause of zebra chip, and develop an action plan to reduce
or eliminate psyllid population during the growing season.
So, what are potato psyllids? They are small insects, about
three millimeters long that feed on your crop. The three life
stages of the psyllid (egg, nymph, adult) are found on potato
plants, and move to new plants throughout the season.
Psyllids are most likely to infest potatoes during tuber initiation
or times of drought stress. If left untreated, psyllid population
will increase, and yield losses of 85 percent or more might be
experienced. Early zebra chip infections can lead to no tuber
production, and late zebra chip infections can impact tuber
chip and fry quality.
Management of the zebra chip problem depends on effective
control of psyllid population, so adopt an aggressive scouting
and chemical-control program throughout the season,
beginning with pre-plant operations and continuing until
right before harvest. Be sure to follow your local guidelines
for timing and sampling procedures. A seed treatment
insecticide/fungicide, like CruiserMaxx® Potato, can protect
your crops from potato psyllids and other insects along with
disease pathogens, offering broad insect and disease control
all the way through the season.