Deer are forced during droughts to congregate at scarce water supplies. Fox said the cracked, muddy flats were breeding grounds for the midges.
There are more than 600,000 whitetail deer in Kansas and Fox doesn't think the outbreak has hurt the population. He said such periodic events can help herds build immunity to diseases.
"There's so much that we don't know," Fox said. "Deer are a large animal and they can withstand weather like drought and heat probably better than the smaller animals. They are so adaptable."
Doug Nygren, chief of the fisheries program, said recharge from rains help, but the rates vary by region. For example, lakes in eastern Kansas can get 10 inches of water per acre per year in runoff while western areas see only one-tenth of an inch per acre a year.
"We're not out of the woods yet. It's a least a two-year process to refill and restock those that have gone dry," Nygren said.