Asian citrus psyllids (ACP) found in Nogales, Ariz. Oct. 6 and Yuma, Ariz. Sept. 30 have tested negative for citrus greening disease, also called Huanglongbing (HLB) disease.

USDA-APHIS in Beltsville, Md., confirmed the negative HLB results on an adult female ACP found in a residential grapefruit tree in Nogales located one-quarter mile north of the U.S.-Mexico International Port of Entry in Nogales.

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

The Sept. 30 insect caught in Yuma County was found just off Interstate 8. It too was likely a passenger on a vehicle or blown into the area by the wind.

The ACP is a huge concern for U.S. citrus industry. The insect is the primary vector of HLB, a dreaded disease which kills every citrus tree it infects.

ACP insects have been found before in Yuma County and at various locations in Southern California. All insects have tested negative for HLB.

Florida, California, and Arizona are the nation’s top three citrus-producing states, respectively. Florida has the ACP and HLB. The disease has resulted in massive tree removal and significant financial losses across the Florida citrus industry.

Fruit from an HLB-infected tree is unmarketable due to its extremely sour taste and odd size.

Two ACPs were found earlier this year at the Nogales border crossing in passenger cargo.

The Nogales finds are the first outside of Yuma County.

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

Before APHIS released the ACP-HLB negative findings, ADA and APHIS had discussed establishing an ACP quarantine in the Nogales area. Usually a single find does not trigger a quarantine, Caravetta told Western Farm Press. A quarantine is likely if an active infestation is found.

Parts of Yuma County and Southern California are under quarantines.

“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 disease area is located about 240 miles south of Nogales in the southern part of the State of Sonora.

The recent Nogales ACP find brings to 41 the total number of psyllids found to date in Arizona. One find was in commercial citrus (Yuma County). The balance was found in residential areas.

Yuma County is Arizona’s largest citrus-producing county with lemons as the top crop.

The ACP was first found in Arizona in Yuma County in Fall 2009. ADA and APHIS established a quarantine in parts of Yuma County which remain in effect. The quarantines impact the movement of citrus in and out of the area.

The ACP was first found in California in San Diego County in Fall 2008. The insect was later found in Imperial, San Bernardino, Los Angeles, and Orange counties. Quarantines are in effect in certain areas.

As the fall holiday season approaches, Caravetta says the Asian citrus psyllid is a reminder for the general public not to transport backyard-grown citrus or give the citrus as gifts.

“It’s not safe to move residential citrus that has not been commercially processed (cleaned),” Caravetta said. “We’re trying to discourage this behavior due to the threat it presents. This insect is so small but it carries a powerful punch that can be very devastating.”

cblake@farmpress.com