For example, the bacteria are thought to rely on adhesive proteins to be able to stick to the gut wall, while others are likely to suppress the insects' defenses.

"We surmise the bacterium break through the gut wall and escape into the blood and that's how they reach the oral region," she said. "But we don't know how that happens. Do they use an enzyme?"

"If we could figure out what enzyme was employed by the bacterium to leave the gut, we could find ways to prevent that from happening, so the bacteria would remain trapped and couldn't get into the plant. Similarly, if we know what it uses to adhere to the gut wall, we could interfere with that process so the bacteria could never grow to large numbers. Or, if we could figure out what they use to get into the salivary region before they get into the plant, we could arrest the pathway in that step."

According to John Caravetta, associate director of the Arizona Department of Agriculture, the state's citrus industry contributes some $37 million, not counting the economic impact of citrus nursery stock produced for ornamental use by homeowners.

"So far, we have been successful in fighting the incursion of the Asian citrus psyllid, which has been detected in 53 sites since October 2009," Caravetta said. "Given that we are under constant pressure from surrounding areas like California and Texas, the big issue right now is to prevent the spread of the insect and the bacterium from entering the state."

He said that his department has been working closely and successfully with the federal agency, the commercial growers, UA's Agricultural Cooperative Extension Service and the public to keep the pests at bay. Through public service announcements and outreach geared toward the public and the master gardeners in the extension offices, the goal is to communicate the risks of moving fruit or trees.

"Our success relies heavily on the participation of the public," Caravetta explained. "We ask the public to either purchase and consume fruit from commercial sources, especially when travelling, or fruit locally produced and sold at Farmer's markets, and to purchase citrus plants from outlets such as local nurseries and garden centers."

"The response from the community has been outstanding," he added. "Don't move citrus, and you won't move the problem."