2019-8-1_PR Comm Packet - Laserfiche WebLink

Home

SURVEY The MDA trained many cities on visual survey techniques. The MDAs EAB Best Management Practice guidelines had the EAB activeflight period begin on May 2. The two areas circled in red have accumulated enough degree days for EAB to begin emerging. The majority of the state hasnt been warm enough for emergence. The MDA assessed winter impacts on EAB during sampling efforts this spring at Fort Snelling State Park, Sauk Centre and Duluth. Many larvae were visibly discolored and dead at the point of sampling. Larvae that appeared healthy and were not injured during sampling were removed from trees and held in a warm area. Over a period of a few days the larvae were periodically prodded and any that moved at some point were counted as alive, any larvae that failed to move at any point were counted as dead. Based on the data we estimate the following levels of EAB mortality at these sites (temperature estimates from MN DNR Climate Data, www.dnr.state.mn.us/climate/index.html): o 82-99% EAB mortality at Sauk Centre, air temperature dropped below -30 degrees Fahrenheit o 67-89% EAB mortality at Duluth, air temperature dropped below -30 degrees Fahrenheit o 40-86% EAB mortality at Fort Snelling, air temperature dropped below -20 degrees Fahrenheit o The low end of each estimate is the percentage of larvae that were visibly discolored and dead, the high end includes the larvae that were not discolored but did not move while being held under warm conditions. In each infested area, at least some portion of the population survived and populations will quickly rebound 42