Is there a 7-year locust and...

There are some cicadas (erroneously called locusts) that appear on a 13-year or 17-year cycle, but these may not necessarily be the ones you remember swarming in Kentucky. Locust swarms occur when this grasshopper-type species (there are more than 1,500 varieties) are in “marginal regions” that don’t offer them suitable habitat. This can occur when they’ve spent too much time in nice places and their numbers have outgrown the space. Locusts can migrate long distances and their swarms can be extremely destructive. The species in Kentucky was probably the Rocky Mountain locust or the migratory grasshopper, responsible for destroying many prairie farms in Canada and the United States. A locust swarm, or plague, is almost impossible to stop or control.