https://www.agriculturedive.com/news/florida-oranges-climate-change-citrus-greening-citrus/736270/
“In the United States, citrus greening was discovered in Florida in 2005 and has since spread to Georgia, Alabama, California, Louisiana, South Carolina, and Texas. The affliction, which Joyner calls “the most difficult disease known to citrus worldwide,” is spread by a tiny insect called the Asian citrus psyllid.
Once infected, trees slowly die over the course of two to three years. While affected trees can still produce some fruit, yields are significantly decreased and the citrus produced is often discolored, bitter and lopsided.
In 2023, scientists at USDA’s Agricultural Research Service shared a potential remedy for the disease by augmenting a tree’s natural immune system. Gene-edited plants that produce receptor proteins can recognize pathogens and then activate a tree’s own immune response.
Commons tactics have been treating orange trees with antibiotics and protecting young trees with mesh bags. This only prolongs their lifespan by a few rather than getting rid of the problems. In the meantime, the USDA has invested more than $400 million to address citrus greening, including more than $57 million through the Citrus Disease Research and Extension Program since 2014 to come to long-term solutions.
While the potential remedy from USDA is still being tested, the department said gene-edited trees could give growers a chance to combat citrus greening without pesticides or removing affected trees from orchards.
In the meantime, many growers and researchers have focused efforts on plant growth regulators as a way to promote tree health and prevent production losses. Chemicals such as gibberellic acid and 2, 4-D have been found to support healthier trees with reduced fruit drop and increased production.
Initial research with growers showed that trees treated with plant growth regulators retained more fruit, even in the face of natural disasters. Treated trees were also more likely to retain fruit in freezing temperatures, opening more possibilities for citrus resilience in the face of its varied challenges.”