Here’s the buzz on how Iowa is going to fight the spreading and tree-killing emerald ash borer: by releasing wasps that kill the borers’ larvae, but don’t sting people. The tiny wasps, smaller than a grain of rice, lay eggs inside the larvae, which prevents them from developing. The U.S. Department of Agriculture came up with the wasps, which have been released in 23 of the 25 states where the borers have been confirmed. The first release in Iowa will be in the next few weeks in Jefferson County, where the Fairfield area has been fighting pests.