DOVER, Del.- Delaware agriculture authorities are alerting local businesses and buyers of tropical nursery stock of the recent detection of fire ants in a shipment of palm trees imported from Florida.

The red imported fire ants were detected during a routine check at a Sussex County business by the Delaware Department of Agriculture's Plant Industries nursery inspection team. The department said a "hold and control order" was promptly issued, and a treatment program to eliminate the fire ants is underway.

"Buyers of tropical nursery stock such as palm trees should carefully inspect their plants for small, aggressive red stinging ants," said Stephen Hauss, cooperative agricultural pest Survey coordinator for the Department of Agriculture. "We need these to be reported quickly and promptly to keep them from spreading or staying in Delaware over the winter."

Ag officials said the imported fire ants are small (3-6 mm long) red to reddish brown ants. Mounds can be 18 inches high and three feet across, and have no visible external opening, unlike ant hills.

Worker ants can sting repeatedly, and will attack anything that disturbs their mounds or food sources, according to officials. Stings are very painful, and venom from a fire ant attack can cause a variety of symptoms in humans and animals. Anyone finding a suspicious ant should call DDA’s Plant Industries Section at 302-698-4500 or 800-282-8685 (toll-free for Delaware only).

A federal quarantine is in place for fire ants in part or all of Alabama, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, New Mexico, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia and Puerto Rico, covering more than 367 million acres. The U.S. Department of Agriculture only allows shipments of nursery stock from quarantined states with an inspection certificate.

Faith Kuehn, DDA's plant Industries administrator, said anyone who travels in those states should not bring plants or plant material back into Delaware that has not been properly inspected; plants should be accompanied by a state inspection certificate. Nurseries or other vendors should check each shipment received for the proper credentials and inspection certificates.

"We are urging caution on all fronts because of the ability of fire ants to spread quickly and the danger they pose," Kuehn said. "We have had good luck so far keeping the Red imported fire ant from becoming established in Delaware, but that depends on prompt reporting and inspections."

Imported fire ants pose a hazard to both human and animal health and to agriculture. Young animals and young trees are both susceptible to ant stings, while nests in fields can interfere with cultivation and harvesting.

Ag authorities say when their nests are disturbed, they can be very aggressive, crawling up vertical surfaces and biting and stinging in a swarm. In addition, if red imported fire ants were to become established in the state, their aggressive habits would have a negative impact on a wide variety of outdoor recreational activities. More information on red imported fire ants can be found at www.aphis.usda.gov.