Although, Brazil is expected to harvest the globally largest cotton crop in the 2023-24 season, Ramularia, a disease, which has been attacking cotton crops is raising concerns among Brazilian farmers.
The 2022-23 cotton crop too was the largest Brazilian crop in its history, when harvest reached 3.2 million tons, up 27 percent over its earlier season.
The yield for the 2022-23 cotton crop also set a record at 1,931 kg per hectare, an increase of 7 percent over the earlier record achieved in the 2019-20 season
Despite these notable results, challenges like combating the Ramularia disease persist for farmers to maintain cotton production levels in the current season.
Ramularia gained relevance in the last decade and has become the most serious challenge in cotton cultivation.
Ramularia is responsible for causing losses of up to 75 percent in productivity and has been identified in all regions where cotton is grown.
The spread of the disease is favored by the action of winds, starting from the first lesions, and covering vast areas in the producing regions.
The disease causes a reduction in the photosynthetic capacity of the plant, which impacts flowering, fiber formation, and quality and causes early defoliation and a drop in productivity.
The initial symptoms are small angled lesions, delimited by veins, on older leaves, and during the plant’s reproduction phase.
As the disease develops, white patches with a powdery appearance are observed. The fungus starts on the lower part of the leaf and can progress to the upper part when environmental conditions are high in humidity.