EN 
PT_BR 
The green corn leafhopper ( Dalbulus maidis The disease, considered the main pest of the crop, has caused billions of dollars in losses to Brazilian production. A new study has quantified the economic impact of the diseases that cause it. corn dwarfism In Brazil, between 2020 and 2024, Brazil lost an average of 22.7% of its corn production due to these diseases, whose pathogens are transmitted by the insect vector, resulting in annual losses of approximately US$$ 6.5 billion.
Over the four agricultural years covered by the study, accumulated financial losses reached US$25.8 billion, as approximately 2 billion 60-kilogram bags were not produced.
The results were obtained from the analysis of data from the National Supply Company (Conab) which cover historical series on productivity, grain production and area planted with corn since 1976, and estimated the economic losses associated with crop damage in the main corn-producing regions of Brazil.
The results were published in the international journal. Crop Protection They detail how diseases that cause dwarfism in corn and the green leafhopper have evolved from a minor problem to the biggest challenge faced by corn production in Brazil in recent decades. The study was conducted by Embrapa Cerrados (DF), by the Agricultural Research and Rural Extension Company of Santa Catarina ( Epagri) and by the Brazilian Confederation of Agriculture and Livestock (CNA).
An overview of the losses
In addition to statistical data, the researchers used information collected by the project. Future Field , an initiative of the CNA and the National Rural Learning Service ( SENAR The surveys were conducted in 34 municipalities representing the main producing regions of Brazil, with the participation of farmers and specialists. Based on technical consensus, they identified and estimated the losses associated with the green leafhopper and the dwarfism symptom complex in each municipality and crop season.
In the first crop analyzed (2020/2021), the impact was greater – a production loss of 28.9%. In the 2023/2024 crop, the index fell by 16.7%. Meanwhile, expenses with insecticides for leafhopper control increased by 19% in these four crops, exceeding nine dollars per hectare, which significantly increased production costs for farmers.
"The results indicate that diseases that cause dwarfism in corn led to an average loss of 31.8 million tons per year," he points out. Charles Oliveira , researcher at Embrapa Cerrados and author of the study. In approximately 80% of the locations surveyed, leafhoppers or leaf damage were identified as the main factor responsible for the drop in productivity.
Larissa Mouro, coordinator of Campo Futuro, highlights the importance of the study for the productive sector: "The data allowed us to generate a consistent economic estimate that covers the entire country."
The threat of dwarfism diseases
Brazil is the world's third-largest grain producer and one of the leading exporters. According to data from Conab, the 2025/2026 harvest is expected to yield 138.4 million tons, with an approximate production value of US$30 billion.
Currently, there are two types of dwarfism in maize — the pale mottled ( Spiroplasma kunkelii ) and the red mottling ( Phytoplasma asteris “Candidatus” These diseases represent the greatest phytosanitary threat to Brazilian grain production. Both diseases are caused by the green leafhopper, which also transmits the maize streak mosaic virus and the maize streak virus.
According to the Embrapa researcher, the problem is aggravated by the lack of preventive treatments for these diseases, which can result in total crop loss, especially in fields planted with hybrids susceptible to them.
Although the pathogens have been known since the 1970s, outbreaks have become frequent since 2015. "Changes in the production system in recent decades, such as the expansion of double cropping and the cultivation of corn for most of the year, have created favorable conditions for the survival of leafhoppers and microorganisms," explains Oliveira.
According to Tiago Pereira, technical advisor at CNA, the green leafhopper is no longer a localized problem: “We are talking about losses that directly impact farmers' income, production stability, and the country's competitiveness. The difference with this study is that it translates this recurring perception into scientifically based data.”
Integrated management and good agricultural practices
Photo: Charles Oliveira
The green corn leafhopper has a high reproductive and dispersal capacity. Because it is found throughout Brazil, it is a difficult species to manage. Biological control with entomopathogenic fungi, natural enemies of the pest, has proven to be a management alternative that can be combined with chemical control and is an important option for the system, since some populations of the green corn leafhopper have already developed resistance to certain classes of insecticides.
Since control based solely on chemical insecticides is insufficient, research recommends adopting a set of practices:
– Elimination of volunteer corn (plants that sprout outside of harvest season due to grain loss during harvesting and transportation): this interrupts the life cycle of the vector and the pathogen.
– Coordinated planting: avoids long planting periods that facilitate the spread of leafhoppers between fields.
The use of resistant or tolerant cultivars maintains high levels of productivity even under disease pressure.
– Initial management, which involves the application of chemical and biological controls during the early stages of plant growth (up to the V8 stage), prevents the infection from causing more severe damage.
– Monitoring: This involves constant and coordinated surveillance among neighboring farmers.
