Florida’s beloved oranges are being threatened by an Asian bug called the Asian psyllid that is spreading a tree-killing disease known as citrus greening. The psyllid is about the size of a pin head, but these little bugs can cause a lot of damage; the psyllid has a tiny bacterium that enters the tree, and the psyllid sucks on leaf sap and leaves. The bacteria is able to move through the citrus tree through its veins, starving the tree of nutrients and damages its roots. Because of the lack of nutrition, the tree produces fruits that are green and unsuitable for use. The veins of the tree’s leaves will turn yellow, and this yellowing typically spreads throughout the tree over the course of a year; this causes oranges to drop prematurely and the fruit contains aborted seeds and has a salty, bitter taste. Trees infected by citrus greening may not show signs for several years. The insects live in the tree itself for about a month, according to the University of Florida (UF), and the females can lay as many as 800 eggs at that time. The psyllid was first found in Florida in 1998 and has been causing damage since 2005. According to the Florida Department of Citrus, the orange harvest could fall to 27 million boxes by 2026- that’s an 82 percent drop from the 149.8 million boxes of oranges in 2005. The U.S. Department of Agriculture reports that the harvest will shrink to 74 million boxes for the season that began in October, which will make the harvest the lowest it’s ever been since 1964. In order to restore production, the industry will need to plant over 20 million trees in the next ten years. Solutions to this deadly infection are few in number. A trial short-term approach includes thermotherapy, where growers will encase their trees in tents and use steam to kill the bacterium without directly hurting the plants. Some growers also may apply nutrients directly on the trees’ leaves or even use pesticides, although too much can burn the fruit; the insects have also developed a resistance to certain chemicals, so using chemical warfare isn’t always the solution, according to Bloomberg Business. However, scientists at the UF say they have found a new weapon to fight back against citrus greening: genetically modified trees. By using a gene isolated from a mustard plant, the researchers are able to create new trees that possess increased resistance to greening and decreased disease severity. They found that some of the trees even remained disease-free 36 months after being planted in a field with a high amount of diseased trees, according to a press release released by UF. The researchers plan to further their research by transferring the gene into commercial plants and rootstocks that grow in Florida to continue to fight back against the citric greening bacteria.
Genetically modified trees could save Florida’s oranges