Two environmentalist groups have filed a lawsuit against the U.S. government in an attempt to get the disappearing bumble bee recognized as an endangered species, Reuters reported.

The lawsuit, filed Tuesday in U.S. district court in Washington D.C., claims that bumble bees are disappearing at alarming rates from their natural habitat in the prairies of the Midwest, Reuters reported. Factors including urbanization, the use of harmful pesticides and disease are wiping the bees out, environmentalists claim.

"The leading hypothesis suggests that disease may be playing a role," Sarina Jepsen, program director at the Xerces Society, told Reuters.

The Society along with the Natural Resources Defense Council filed the suit against the Interior Department and the U.S. Fish and Wildlife Service. Jepsen said they tried to get the Interior Department to list the bee as endangered last year, Reuters reported. They decided to file the lawsuit when nothing was done.

If the environmentalists are successful, the rusty-patched bumble bee will be the first bee species listed as endangered. The exact number of bumble bees left is not known. However scientists say their numbers have decreased 95 percent when compared to other species, Reuters reported.

Wild bumble bees, which pollinate several types of plants and crops, are used to help grow tomatoes in greenhouses. Jepsen said the bees most likely contracted diseases from coming into contact with other bee species also brought into the greenhouses.

The Fish and Wildlife Service told Reuters they consider all requests for endangered listings, but could not comment further on the pending litigation.

Another bee species, the honey bee, is also disappearing due to pesticides, environmentalists say. The Hawaiian yellow-faced bee is also being considered as endangered, Jepsen told Reuters.

An annual report on the honey bee population from the U.S. Department of Agriculture is set to be released this week.