A single female Asian citrus psyllid (ACP) found Oct. 6 in a residential grapefruit tree in Nogales, Ariz., is undergoing tests at the USDA-APHIS laboratory in Beltsville, Md., to determine if the insect carried citrus greening disease, also called Huanglongbing disease (HLB).

Test results are expected later this week. APHIS confirmed the insect was an ACP Oct. 7. Nogales is located in southern Arizona at the U.S.-Mexico border.

The insect was found in an APHIS trap in a residential backyard about one-quarter mile east of the International Port of Entry in Nogales.

The ACP is the primary vector of HLB. The dreaded disease kills every citrus tree it infects. The insect was previously found in Yuma County, Ariz. and at various locations in Southern California.

HLB, the most deadly citrus tree disease in the world, is not found in Arizona or California. In Florida, ACP and HLB have caused massive tree losses. Fruit from an HLB-infected tree is unmarketable due to its extremely sour taste and odd size.

John Caravetta, Arizona Department of Agriculture Associate Director and Chief of the agency’s Plant Services Division, says additional trapping in Nogales is underway to determine if the insect was a hijacker on a vehicle, blown in by the wind, or part of an established colony.

“Based on the trapping results so far we don’t believe the psyllid is established in the Nogales area,” Caravetta said. “It was probably a hitchhiker that may have come across in commercial or passenger traffic or even blown in from an area that already has the psyllid.”

Caravetta says insecticide control treatments will only be applied in the Nogales area if an active infestation is found. If that is the case, foliar and drench-applied insecticides would be applied within a 1,200-foot distance around the find.

ADA and APHIS have discussed establishing an ACP quarantine in the Nogales area. Usually a single find does not trigger a quarantine. A quarantine is likely if an active infestation is found.

In addition to the recent ACP find in Nogales, two psyllids were found in passenger carry-ons early this year at the Nogales border crossing.

“This further shows that International Ports of Entry are significant pathways which create additional challenges for border States,” Caravetta said. “This pest has a real presence and opportunity to enter Arizona through commercial and passenger traffic. We keep crossing our fingers that we don’t have an introduction of an adult psyllid with HLB.”

HLB is found in several locations in Mexico. The closest Mexican HLB-infected ACP colony is located about 240 miles south of Nogales in the southern part of the State of Sonora.