U.S. states seeking exemption use of kasugamycin on apple

Michigan officials are seeking a federal exemption to use an unregistered pesticide on up to 10,000 acres of apples trees that are susceptible to a deadly disease. The bacteria causing the disease have grown resistant to current treatments. The spray-on fungus killer, kasugamycin, would control fire blight, which has been on the uptick in Michigan orchards the past few springs.

The bacterial disease attacks apple and pear trees’ blossoms, shoots and limbs. Branches, leaves and trees look scorched when infected. The disease is sporadic, hard to control and usually attacks in the spring. Fire blight primarily affects southwest and northwestern Michigan and, if allowed, will only be used in 10 counties in those regions.

"Fire blight is just so detrimental,” said Nikki Rothwell, a district horticulturist with the Northwest Michigan Horticulture Research Center. “It comes during the bloom, bacteria builds up in flowers and rain can flush it out and cause an infection.”

Kasugamycin is an antibiotic and would kill the bacteria. For years apple trees have been treated with a different antibiotic, streptomycin, but the bacteria are growing resistant to it. It is said that the department has requested and received the exemption the past three years.The request entails no more than three applications of the pesticide, on no more than 10,000 acres between April 1 and May 31, 2012. The maximum amount sprayed will be approximately 30,000 gallons.

The EPA is accepting public comment on the request for exemption until Feb. 6.