>Severe pink rot has been identified in several fields in central and eastern Idaho, according to the Treasure Valley Pest Alert Network.
Jeff Miller, University of Idaho pathologist, said plants appear wilted with leaves dying and the plants lying down. This is different from the ty pical flagging symptoms associated with verticillium wilt, he said.
Infected plants are showing lesions on the belowground stem that resemble severe rhizoctonia. Infected stem tissue easily sloughs off. The pathogen grows from an initial below-ground infection up and down the stem.
Miller says tubers are becoming infected by the pathogen growing out of the stolon or by direct contract if tubers are touching infected stems.
Some fields have shown extremely high infection rates. In these cases, immediate vine kill is advised to prevent the pathogen from growing into healthy tubers.
Extended extremely high temperatures experienced over the last several weeks most likely led to the severity of the problem. Maximum soil temperatures have been above 80 degrees F for much of July and the early part of August.
Extra water that may have been applied to help manage heat stress has compounded the pink rot problems. The University of Idaho would like to receive samples in order to determine fungicide sensitivity.
Growers are asked to contact Miller at (208) 397-4181 by or e-mail jsmiller@uidaho.edu.