An orange juice brick, one morning in September in France, might seem like an ordinary start to the day. However, the fruit that fills it most likely came from Brazil, a country now facing a serious threat to its citrus industry. This threat is a bacterium known as Candidatus Liberibacter asiaticus, the cause of a disease called citrus greening, or huanglongbing. This disease has already severely impacted Florida’s citrus industry, where orange production has dropped by 90% over the past 30 years since its arrival in 2005. Now, Brazil is experiencing a similar crisis, with nearly 44% of its citrus trees infected by the same bacterium, which currently has no known cure. The mechanism behind the spread of the disease is straightforward but devastating. A small insect, the Asian citrus psyllid (Diaphorina citri), bites citrus trees and transmits the bacterium. Once a tree is infected, it cannot recover. The fruit becomes bitter and inedible, falling prematurely, and the tree eventually dies within a few years. Without resistant citrus varieties or effective treatments, the disease spreads rapidly. The psyllid was first detected in Florida in 1998, and the disease was identified there in 2005. Brazil followed a similar path, with the disease being discovered there in 2004. Both countries now face the same threat, but their responses and outcomes have differed significantly. Florida, once the dominant force in global orange production, has seen a dramatic decline. In the 1997-98 season, Florida produced a record 244 million boxes of oranges, a peak that marked the height of its citrus industry. Today, production has dropped to around 18 million boxes for the 2023-24 season, with projections suggesting it may fall further. This decline has led to the collapse of many citrus farms and processing plants, with the number of citrus growers in Florida dropping by 62% between 2002 and 2017. The industry that once defined American agriculture has been severely weakened. Brazil, the world’s second-largest producer of oranges, is now facing a similar crisis. The country supplies the majority of concentrated orange juice consumed in Europe, and the spread of citrus greening is accelerating. In 2024, nearly 44% of citrus trees in key regions of Brazil were infected, up from 38% in 2023. This means that almost half of the citrus trees in these regions are affected, with about 90 million trees infected out of a total of over 200 million. Despite efforts to control the spread through strict management practices, the disease continues to progress, raising concerns about the future of Brazil’s citrus industry and, by extension, the availability of orange juice in Europe. The lack of a sustainable solution remains a major challenge. There is no curative treatment for infected trees, and no widely available resistant citrus variety exists. The only options are preventive measures, such as replanting disease-free trees, controlling the psyllid population, and removing infected trees before they spread the disease. While Brazil has managed to slow the impact of the disease better than Florida through strict protocols, the continued rise in infection rates suggests that the problem is far from being under control. As the situation in Florida shows, without a breakthrough, the future of global orange juice production—and its cost and availability—could become increasingly uncertain.