A small number of potato psyllids have been trapped in North Dakota and Minnesota potato fields from mid-June through mid-July, but none has tested positive for the Liberibacter bacterium responsible for zebra chip.

Nevertheless, researchers say they are still cause for concern since potato psyllids can cause leaf yellowing and rolling just by feeding on potato plants, according to a grower newsletter.

Andy Robinson, an assistant professor and North Dakota State University Extension potato agronomist, recommends growers keep scouting fields for potato psyllids and monitoring psyllid traps.

For more information on potato psyllids, including registered pesticides for use in North Dakota, download the 2012 Field Crop Insect Management Guide.