To develop more effective ways of controlling psyllids, geneticists have begun mapping the insect's genome. And already, comparisons of the psyllid against fully mapped insects like the fruit fly and mosquito are allowing scientists to rapidly gain knowledge of the psyllid's physiological processes, according to Robert Shatters, a scientist at the U.S. Horticultural Research Laboratory.
Shatters and his fellow researchers are looking at ways to block some aspect of the psyllid's feeding or digesting process, he said. Through analysis, his lab is determining what genes are used for taking in food, he said, and if you "block those, then the plant is no longer a suitable host."
Other geneticists are interested in "lethal genes," Shatters said, which "mess up development." It could be a gene that, harmless when inserted into a male psyllid, will render any female heirs of that modified insect infertile or dead. Researchers can already do this in lab situations, he said, by blocking genes with RNA interference, a recently adapted biological process that allows nearly any gene to be easily silenced.
There are challenges ahead, Shatters said. Breeding a large population of modified psyllids would be difficult, since they only feed on citrus. In his rosiest projections, within four years, his lab could be testing its modified psyllids in the field.
Shatters and others suspect a multitiered effort will be needed to stop the disease. A resistant tree like those possibly developed by Texas A&M would seem to be the easiest solution, he said.
"But we do know with biology there is the dance of evolution," he said, warning that the psyllids could adapt to modified citrus trees.
Such solutions cannot come quickly enough for Florida's embattled citrus industry, which has been stressed since the 1990s.
"Developers were gobbling up land as well as disease gobbling up land," said Mark Fagan, a spokesman for Florida's citrus programs. "Yes, there has been a loss of acreage."
Many growers have had their groves for generations and do not want to give them up for real estate development, Fagan said, but the devastating effect of HLB could finish many groves off.
While other diseases, like canker, may leave lesions on oranges, they do not change taste, allowing fruit to be juiced, Fagan said. Not so with HLB.
"Fruit with HLB, [it] can't be juiced or eaten," he said. "It has a horrible taste. The tree is just completely useless."
Reprinted from Greenwire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500