Potato fields In Iowa for several years have suffered from "burning," which has seriously cut the yield of this crop. The trouble has been called tlpburn. Its cause was unknown until recently, when It was discovered that It Is due chiefly to the potato leafhopper, a little green, fly-llke Insect that appears In enormous numbers during the summer. The Iowa Agricultural Experiment Station has verified this connection between the leafhopper and tlpburn or "hopperburn" and control measures have been devised.