The citrus researcher says the 500-pound gorilla question is how was HLB brought into Texas? The adult psyllid hitchhikes on fruit in bins and on semi trucks. There is concern the disease may have been on Mexican limes imported from Mexico to Texas. HLB has been found in Mexico in Mexican lime production areas.

On Dec. 7, 2011, Ray Prewett, president of Texas Citrus Mutual, sent a letter to USDA-APHIS Administrator Gregory Parham expressing concern that imports of Mexico-grown limes into Texas could have psyllids carrying the HLB bacterium.

Prewitt’s letter said HLB was in 17 of Mexico’s 23 citrus-growing areas — the closest find 130 miles from Texas commercial citrus production.

Prewett said shipments of Mexican key limes from the Mexico State of Colima and Persian (sweet) limes from the State of Veracruz are of the most concern to the Texas citrus industry. Limes are a preferred psyllid host due to frequent flush cycle characteristics of lime plants.

Prewett expressed concern over the low inspection rate of imported limes. Many limes enter the U.S. through Texas’ Pharr and Progreso ports of entry. During 2010, the USDA Agricultural Marketing Service recorded 15,560 truckloads of limes entered the U.S. through the Texas ports of entry. Most of the shipments originated in the states of Colima and Veracruz.

Lime imports fall under the guidelines of the National Agriculture Release Program where only 1 in 50 loads are inspected to ensure that leaf and stem material in the shipment is within set limits. 

Prewett said adult psyllids had not been found in shipments to date. Yet psyllids could be present but not seen due to the insect’s almost microscopic size (one-quarter inch) and its high degree of motility when disturbed.

With thousands of truckloads of limes entering Texas each year from known HLB infected areas, Prewett said USDA has a responsibility to protect Texas citrus growers from an HLB infection from Mexico.

Prewett said, “We are requesting that a formal risk assessment be initiated as soon as possible to include packing house operations at the point of origin; survivability of adult psyllids under normal shipping environmental conditions; presence or absence of adult psyllids upon arrival at destination; and a determination of HLB positive or negative of any psyllids found.”

Wright says infrequent citrus inspection is also likely at Arizona’s port of entry in Nogales. “Imported limes from Mexico could be a real risk and we’re not paying enough attention to it as a citrus industry,” Wright said. “We are running into issues of people wanting continued U.S.-Mexico agricultural trade but without fully considering the disease implications.”