“Sugarcane wilting has been observed in all producing regions in central-southern Brazil, with varying intensity…”
Sabrina Chabregas is director of research and development at the Sugarcane Technology Center (CTC), an agronomist from ESALQ/USP, with a PhD in Genetics and Plant Breeding and an MBA in Business Management from FGV.
AgriBrasilis – What are the impacts of Sugarcane Wilt Syndrome?
Sabrina Chabregas – Sugarcane Wilt directly affects the stalk, reducing both TCH (Tonnes of Sugarcane per Hectare) and ATR (Total Recoverable Sugar). This disease degrades the tissue and converts sucrose into fructose and glucose, compromising the quality of the raw material. It is estimated that each 1% incidence causes an average loss of 0.5 tonnes/ha.
During field visits conducted by the CTC team of plant pathologists and technicians, areas with up to 40% of culms attacked were found. In addition to agricultural losses, there are extra industrial costs, such as the use of antibiotics to maintain fermentation, and the risk of a drop in sugar quality.
AgriBrasilis – What is its scope and which regions are most affected?
Sabrina Chabregas – Sugarcane wilt has been observed in all producing regions in central-southern Brazil, with varying intensity. The highest occurrences were recorded in the Triângulo Mineiro region and in southeastern Goiás, which is the most affected region. There is also evidence in São Paulo and Paraná, although with a lower incidence. I would like to take this opportunity to invite farmers to register on the Esfera platform (https://esfera.circle.so/feed) to share their insights and expand regional monitoring. This will allow for a more in-depth view of the incidence and conditions that favor the disease in each region. The information generated on the Esfera platform will be shared with everyone.
AgriBrasilis – What are the symptoms of wilting and how can it be distinguished from other diseases, such as red stalk rot?
Sabrina Chabregas – The visible symptom of cane wilt is the retraction in the middle third of the culm, which takes on a “half-moon” shape. Internally, there is unilateral tissue degradation, but the tip leaves remain green, making detection in the field difficult.
Both cane wilt and red stalk rot are caused by the same pathogen and present internal redness, but in red rot there are lesions caused by the borer, which serves as a gateway for the fungus. In wilt, there are no perforations, and the tissue in the retracted area becomes soft or “limp.”
“Now that we have identified the causal agent, we can be more assertive in our control measures…”
AgriBrasilis – How does Colletotrichum infect sugarcane and what conditions favor its development?
Sabrina Chabregas – Colletotrichum falcatum is a fungus spread by wind and water, developing best between 25 and 30°C and with high humidity. It is the causal agent of Red Rot in sugarcane, and we have now discovered that it also causes Sugarcane Wilt, which is a new symptom. Understanding where the fungus is penetrating to cause sugarcane wilt is part of the next steps toward a greater understanding of this disease, since no borer damage or entry holes are observed in the culm.
AgriBrasilis – How was it possible to confirm Colletotrichum as the cause of SMC?
Sabrina Chabregas – We used two approaches. The first was metagenomics, which identified and quantified the microorganisms present in healthy and diseased plants. The second was Koch’s postulate, a classic methodology for identifying disease-causing agents: we isolated the fungus and reproduced the symptoms in cultivated plants, with consistency and repeatability.
Scientific tests have shown that Colletotrichum falcatum is predominant in affected plants, while other fungi commonly discussed as possible causal agents, such as Pleocyta, only appear in advanced stages, confirming their opportunistic nature. Fusarium, on the other hand, was practically undetectable in healthy or diseased plants. I would like to take this opportunity to acknowledge the leadership of Luciana Castellani, together with the Scientific Forum, which includes renowned professors and scientists, and the work of the plant pathologists and technicians at CTC who managed to overcome this challenge: Tatiane Mistura, Mariana Cicarelli, Abel Torres, and Jardelcio Ervilha.
AgriBrasilis – What changes in terms of control, improvement, and management methods?
Sabrina Chabregas – Now that we have identified the causal agent, we can be more assertive in our control measures, creating specific protocols and targeting actions. In genetic improvement, we are already testing the resistance of varieties to Sugarcane Wilt, and tolerant parents can be used in crossbreeding programs to generate disease-resistant varieties. In terms of management, practices such as early harvesting in affected areas reduce losses, and keeping the cane less stressed helps to reduce the incidence. Trials with chemical and biological products are underway to define more effective strategies. Identifying the causative agent of the disease was a fundamental step in advancing our understanding and developing effective control strategies for Sugarcane Wilt.
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