University of Idaho reports light potato psyllid pressure

Potato psyllids, like the insect pictured above, can spread the Liberibacter bacterium that causes zebra chip disease in potatoes. Some Idaho farmers are saving a bit of money on insecticidal sprays due to light potato psyllid pressure. #Pressure from the tiny, winged insects that spread zebra chip disease in potatoes has been light this season, emboldening some Idaho farmers to scale back on their pesticide programs. Zebra chip, which is caused by the Liberibacter bacterium and spread by potato psyllids, first arrived in the Pacific Northwest in 2011. The disease creates bands in tuber flesh that darken during frying, rendering spuds unmarketable. University of Idaho Extension entomologist Erik Wenninger, who runs an extensive field monitoring program to gauge psyllid populations, said the first psyllid of this season was captured in late May — about the same timing as last season. However, a single psyllid, captured at UI’s Kimberly Research and Extension Center, has tested positive for Liberibacter this season. Wenninger said zebra chip was found in a few fields last season, but the incidence of the disease was relatively low, especially given the high psyllid densities. More