MANKATO (AP) -- The Minnesota Department of Agriculture said it found no evidence of misuse of a pesticide spray that killed hundreds of monarch butterflies in Gaylord last summer.
An investigation by the Agriculture Department had determined there was enough of the chemical Permethrin in the butterflies to have caused their deaths. The citywide spraying on Aug. 23 -- to ward of mosquitos -- was done late on a foggy day, which would have suspended the pesticide in the air, a report on the findings said.
The report, released Friday, also said there was no evidence to support the claims of health problems by some residents following the spraying.
The findings did raise two concerns: The spray had an active ingredient that was in a higher concentration than indicated on the label, and the city's hired applicator had previously sprayed for mosquitoes even though he did not have proper state licensing.
But Paul Liemandt, enforcement supervisor for the department, said neither of those problems contributed to the butterfly deaths.
A minimal penalty, likely between $300 and $500, will be sought against the city for using an unlicensed applicator in July, Liemandt said. He said the problem with the labeling of the spray sold under the brand name Biomist will be turned over to the U.S. Environmental Protection Agency, which regulates how manufacturers label pesticides.
The morning after the spraying, residents noticed hundreds of dead butterflies around town. Initially, city officials said they did not believe the spraying could have killed the butterflies.
Some residents who were outdoors the evening of the spraying reported rashes, but the Agriculture Department said there was no evidence to link any health problems to the spraying.
Brainerd Dispatch ©2013. All Rights Reserved.