Combatting Citrus Greening in Brazil: Innovative Solutions and Agricultural Advancements

HLB Incidence and Impact

Huanglongbing (HLB), commonly known as citrus greening, poses a significant threat to Brazil's citrus industry, particularly in regions like São Paulo. Over the past three years, the incidence of HLB has increased by 9.16%, with the average incidence rising from 22.37% in 2021 to 38% in 2023, according to Brazil’s citriculture defense agency, Fundecitrus. In highly affected regions such as Brotas, Limeira, and Porto Ferreira, HLB incidence levels have soared to alarming rates of 49.41%, 70.72%, and 74.05%, respectively.

The spread of HLB is now affecting the production of Brazilian oranges and Frozen Concentrated Orange Juice (FCOJ). As a result, the United States Department of Agriculture (USDA) forecasted the Brazilian orange crop for Marketing Year (MY) 2023/24 to be 16.5 million metric tons (mmt). This represents a decrease of 1.03% compared to the MY 2022/23, which was around 16.67 mmt. The decline is attributed to the incidence of greening, which has been affecting Brazil’s citrus belt. Additionally, the average fruit weight is expected to be 158 grams for MY 2023/24, primarily due to unfavorable climate conditions and diseases, resulting in expectations of lower production and fruit quality. Similarly, FCOJ 65 Brix equivalent production for MY 2023/24 is forecasted at 1.05 mmt, reflecting a 1.64% YoY decrease due to the expected low availability of fruit for processing, which has been impacted by extremely high temperatures and the incidence of greening.

Figure 1: Brazilian Orange Production (2021/22 to 2023/24)

Various factors contribute to the spread of HLB in Brazil. The favorable climate in most regions facilitates infection and transmission, while the high density of orchards complicates coordinated disease management efforts. Additionally, inadequate control measures, including the failure to uproot diseased trees and ineffective spraying against HLB-spreading psyllids, have exacerbated the problem.

Innovative Solutions

To address HLB challenges, Brazilian agro-science researchers have developed innovative solutions. A groundbreaking study conducted at the Citrus Center of the Agronomic Institute of Campinas (IAC) resulted in the formulation of an effective management strategy for citrus greening. The study identified N-acetylcysteine (NAC) as a potent tool for combating HLB. Known for its antioxidant properties, NAC demonstrated remarkable efficacy in neutralizing the bacteria responsible for citrus canker and citrus variegated chlorosis.

Based on the success of NAC in managing other citrus diseases, CiaCamp, a Brazilian agricultural research startup, obtained exclusive licensing rights to introduce NAC technology in agriculture. Through a partnership with Amazon AgroSciences, NAC is marketed as a fertilizer under the GRANBLACK brand, offering farmers a powerful tool for controlling HLB and other citrus diseases. Beyond citrus, the technology seems promising in managing diseases affecting crops such as corn and other fruit trees, grapes, and vegetables. The innovative approach CiaCamp and Amazon AgroSciences pioneered represents a significant advancement in agricultural science, offering hope for combating the devastating impact of HLB on Brazil's citrus industry and beyond.

Figure 2: Impact of NAC on Citrus Plants

Conclusion

In addition to aiding in citrus greening management, the fertilizer can mitigate the effects of other environmental aggressions, such as heat, ultraviolet radiation, and water stress, due to its antioxidant action. As a sustainable product, it avoids the generation of waste and its environmental impacts. It can also be applied in association with traditional pesticides currently used. The technology enables a significant reduction in the severity of greening. NAC is not a remedy, but rather a supplement for plants that does not harm the soil, leaves, or fruits. NAC in agriculture is an innovative solution that is expected to benefit Brazil and the global citriculture sector radically.

Stakeholders need to pay attention to the results from farms utilizing NAC during the current production season. If this innovation proves successful, Tridge anticipates that it may go a long way toward hampering the spread of HLB and stabilizing citrus production in Brazil. Other affected countries, such as the United States (US), may also look to adopt NAC to curb the spread of HLB in Florida.