MADISON, Wis. -- A mysterious ailment killing honeybees nationwide might be hitting Wisconsin bees harder than first suspected.

Colony Collapse Disorder has made headlines recently because bee pollination is needed for a third of all U.S. food crops.

One worried beekeeper in Lafayette County who has suffered losses said that good research into CCD isn't possible without good data. Yet, he said he believes some beekeepers in Wisconsin aren't reporting CCD.

"They are lethargic. They're all young. The queen was there until about last week," said Mark Ranum, owner of Ranum's 1887 Brand Apiaries near Darlington, about some colonies that have died off this year.

His 10-acre operation is located in farm country outside Mineral Point, but Ranum said that the mysterious phenomenon is threatening his century-old family business.

"There's probably 12 bees left in this hive," Ranum said, referring to one of 18 colony hives that just died off.

Under normal conditions, there would be as many as 50,000 honeybees in the hive. But CCD, which is also striking thousands of colonies nationwide, has left most of Ranum's hives lifeless.

In fact, he said 240 of his 300 hives have gone silent since late 2005. He said that most of them exhibited classic signs of CCD.

Ranum said the last of some 18 colonies that have died this past spring have lethargic bees, no queen bee and little or no activity. The remaining bees have left the hive and haven't returned. No one knows why, WISC-TV reported.

Ranum said he believes most were victims of CCD, where nearly all of the bees leave the hive and never come back.

"The queen still appears to be laying eggs and the young adult bees are still there, but it appears they're reluctant to eat any of the food that's in the hives and the other bees are just gone. It's like they just disappeared," said Jane Larson, spokeswoman for the state Ag Department.

"The bee cluster has gotten so small that it can no longer sustain itself," Ranum said.

To sustain his operation, Ranum and his family have started packaging fresh produce along with their "1887 brand" honey.

Ranum estimated that from other dead colonies he's seen, CCD has claimed 1,200 colonies or more than a third of the bees in Lafayette County alone.

"For whatever reason, there's been an underreporting of this whole situation," Ranum said.

State CCD inspections are voluntary for the owners of Wisconsin's 64,000 bee colonies.

The state Ag Department wouldn't say the state has CCD -- only that it has seen what appears to be CCD symptoms in some dead colonies officials have inspected.

There are only theories about what's causing the disorder. Ranum said he believes pesticide use along with a mite that bites bees might both be responsible.