One of the tubers sampled recently from a field in Ada County, Idaho, tested positive for liberibacter (Lso), the bacterium that causes zebra chip (ZC).
The sample was taken from a site that has seen a relatively high number of Lso-positive psyllids. Both foliar and tuber symptoms have been difficult to find in this and other fields that have been inspected, so at least in these fields, overall ZC incidence appears to be low.
Nevertheless, risk of ZC appears to be higher this year in Idahothan during the last two, especially in the Treasure Valley, so researchers continue to encourage growers and crop consultants to scout for symptomatic plants and to consider this risk level when making insecticide decisions through the remainder of the season.
Photos of typical ZC symptoms exhibited by foliage and tubers may be found here.