BROOKINGS – It's too early for South Dakotans to begin treating their ash trees for emerald ash borer said John Ball, professor and SDSU Extension forestry specialist.
"Our recommendation, consistent with other states, is not to begin treatments until the insect has been confirmed within 15 miles of your trees" Ball said. "There are companies already going around communities in eastern South Dakota telling people to start treatments now, but this is premature."
The reason? Ball explained that emerald ash borer was recently confirmed near Welcome, Minnesota, and this confirmation, along with the confirmation in Alta, Iowa, earlier this summer, mean the insect is still 100 miles from South Dakota.
The emerald ash borer was accidentally introduced from Asia into Michigan in the late 1990s. It is responsible for the loss of more than 50 million ash trees in this country. None of our native ash species; black, blue, green or white; have shown resistance to this insect.
"Treatments are now so effective that you can even save trees that have been infested for a few years so there is no need to start pesticide treatments now," Ball said.
Ball recommends waiting until emerald ash borer is found in your area and then decide based on cost which ash to treat.
The average cost of treatment is around $80 to $120 a tree. Treatments are done every other year.
"These treatments do work," Ball said. "Today, the only ash trees left in more eastern communities impacted by emerald ash borer epidemics are those that have been treated."
