It has been revealed by state forestry officials on Tuesday that the recent cold temperatures may have destroyed some emerald ash borer larvae, but it is less likely to stop the spread of the tree-killing pests in Iowa. Arctic outbreaks are known not to last for long enough in Iowa.

Tivon Feeley, forest health specialist for the Department of Natural Resources, said that some mortality will be seen, but it is likely to be less than 10%. State Forester Paul Tauke said that what is more worrisome is the fact that the population is highly likely to bounce back within a year even if the mortality rate reaches 50%.

Places like Minnesota are difficult places for emerald ash borer to spread. It is for a simple reason that arctic outbreaks are colder, more frequent and last longer there, said Lee Frelich, director of the University of Minnesota Center for Forest Ecology.

Frelich said that areas like Minnesota and North Dakota have long cold spells due to which, they provide a better chance to ash trees to survive.

"We're outside that zone in Iowa," Feeley said. State Climatologist Harry Hillaker said that Iowa is not that colder as Minnesota and North Dakota are.