An Update on Brazil’s Citrus Diseases

Ernie Neff Brazil, Diseases

citrus diseases
The Asian citrus psyllid transmits citrus greening disease.

An update on citrus diseases in Brazil was part of a recent U.S. Department of Agriculture Foreign Agricultural Service (FAS) report.

According to the 2021 citrus greening survey conducted by Fundecitrus, 43.4 million trees, or 22.37%, of the trees in the commercial area of the state of São Paulo and the western part of Minas Gerais are affected by greening. This figure shows an increase of roughly 7% in the greening infection relative to the 2020 greening survey (20.87 percent). However, if the number of citrus trees eradicated in 2020 due to greening (approximately 8.5 million trees) were included in the survey, greening infection would rise to 26.52%.

The industry is concerned about the upward trend, especially in adult groves. The high number of infected trees over five years old has created difficulties in controlling the disease in young fields. This is because the vector of the disease, the Asian citrus psyllid, multiplies in the infected trees and spreads the bacteria, which causes the disease in the neighboring young fields.

The 2021 Fundecitrus citrus variegated chlorosis (CVC) disease survey reports that the level of infection continues to decrease, at 0.46% or roughly 890,000 trees, as opposed to 1.04% in the previous year. Losses associated with CVC should remain very low given that the infected trees are mostly in the initial phases of the disease.

Decades ago, the industry adopted measures including protected nurseries for seedlings, renewal of old infected citrus groves, and pesticides to control greening, which also controls the spittlebug that transmits CVC. These measures have contributed to the noteworthy drop of the disease.

Citrus canker infection in 2021 is estimated at 10.76% of the trees in the commercial area of São Paulo and Minas Gerais, or 21 million trees, a drop of 38% compared to 2020 (17.26% infection), according to the latest Fundecitrus survey. The prevailing drought weather during several months of 2020 and 2021 contributed to the sharp reduction of the infection level.

The formerly rigid control of eradicating the affected and neighboring trees was loosened up, and risk mitigation was adopted instead. Brazilian legislation allows different states and municipalities to adopt different control/eradication strategies.

See the full FAS report on Brazil.

Source: The U.S. Department of Agriculture’s Foreign Agricultural Service

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