An Asian bug called the Asian psyllid is spreading a tree-killing disease known as citrus greening which is threatening Florida's orange trees. According to the Florida Department of Citrus, the orange harvest could fall to 27 million boxes by 2026- 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.
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.
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.
The tiny psyllid bug can cause a lot of damage by producing a bacteria that is able to move through the citrus tree through its veins, starving the tree of nutrients and damages its roots. Due to 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.
In order to restore production, the industry will need to plant over 20 million trees in the next ten years.
Source: greenepublishing.com