Mirkov conducts his lab research in Weslaco. The transgenic tree greenhouse and field tests are underway at Southern Gardens Citrus, a citrus grower and processor in South Florida.

The tests include a screened psyllid greenhouse where large numbers of infected psyllids fly and land on the transgenic citrus plants, at much higher insect numbers and infection odds than a commercial grower would ever find in a grove.

The other test includes transgenic trees planted next to standard citrus trees in a commercial grove. The standard, unprotected trees are HLB infected with symptoms including yellowed shoots and leaves. The transgenic trees appear much healthier.

Laboratory tests confirm the transgenic trees have lower amounts of Liberibacter bacteria.

Mirkov is convinced that the transgenic tree could be a valuable resource to growers to help prevent the spread of HLB. Mirkov or his research sponsors make quarterly trips to Washington, DC to share his ongoing findings with the Environmental Protection Agency (EPA) and USDA.

“The EPA understands that HLB is a crisis,” Mirkov told the plant pathology crowd.

Mirkov is encouraged by the EPA’s overall positive response to the transgenic research. The agency has made it clear that, in general, transgenic trees must be safe for the environment and the fruit safe for human consumption.

Mirkov and Southern Gardens have studies underway seeking any adverse effects on non-target beneficial organisms, including honeybees.

Mirkov said, “In the long run, I believe EPA and USDA will give approval to proceed forward.”

If approved, Mirkov says the first commercially available transgenic trees could be on the market in two to three years.

Western Farm Press asked Mirkov about any possible consumer backlash over the idea of citrus consumption with a touch of spinach inside.

He responded, “Will my citrus taste like spinach or will my orange juice be green? Of course not. We are talking about a small piece of DNA from spinach placed in citrus.”