Palms from Florida with ants found at Sussex business.

The Delaware Department of Agriculture is alerting local businesses and purchasers 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 DDA’s Cooperative Agricultural Pest Survey team. A treatment program was immediately initiated to eliminate the fire ants.

"Buyers of tropical nursery stock — such as palm trees — should carefully inspect their plants for small, aggressive red stinging ants," said DDA Cooperative Agricultural Pest Survey Coordinator Stephen Hauss. "Red imported fire ants are not known to be established in Delaware. We intend to keep it that way because they are a threat to human health and the agriculture industry. Quick and prompt reporting to the Department of Agriculture will help keep the imported fire ants from spreading or over-wintering in Delaware."

Red imported fire ants are small — 3 to 6 millimeters long — red to reddish brown ants. Mounds can be 18 inches high and 3 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. Stings can be painful, and venom from a fire ant attack can cause various symptoms in humans and animals. Anyone finding a suspicious ant should call DDA’s Plant Industries Section at 698-4500 or 800-282-8685.

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.

"We are urging caution on all fronts because of the ability of fire ants to spread quickly and the danger they pose," said Plant Industries Administrator Jessica Inhof. "We have had good luck so far keeping the red imported fire ant from becoming established in Delaware. A lot of that is due to the vigilance of the vendors, and their promptness in reporting and inspecting imported tropical stock.”

Inhof said that 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. In other states, pine straw mulch has been found to harbor red imported fire ants. Nurseries or other vendors should check each shipment received for the proper credentials and inspection certificates.

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. When their nests are disturbed, they can be aggressive. They will crawl up vertical surfaces, biting and stinging in a swarm. In addition, if red imported fire ants become established, their aggressive habits will negatively impact a wide variety of outdoor recreational activities.

For more, visit aphis.usda.gov.