First report of Thekopsora minima in Brazil
In January and February 2017, symptoms of leaf rust were observed in a commercial blueberry (Vaccinium corymbosum) field, in the municipality of Jaguarão, Rio Grande do Sul, Brazil. The disease started as small reddish-brown leaf spots, with yellowish pustules. As the disease progressed, the leaf spots enlarged, becoming vein delimited, with a reddish-purple halo. At later stages, lesions coalesced, spreading all over the plant, causing severe early defoliation of the plants (especially on cvs Jewel and Snowchaser). Laboratory analysis (morphology, molecular tests, pathogenicity tests to verify Koch’s postulates) confirmed that the causal agent was Thekopsora minima (EPPO A2 List). This is the first time that T. minima is reported from Brazil. The authors noted that further studies are needed to evaluate the risk that blueberry leaf rust may present to commercial fields in Southern Brazil.
The situation of Thekopsora minima in Brazil can be described as follows: Present, only in some areas (first found in 2017 in the municipality of Jaguarão, Rio Grande do Sul).
Sources
Pazdiora PC, Dorneles KR, Araújo Filho JV, Rossetto EA, Guatimosim E, Dallagnol LJ (2019) First report of blueberry leaf rust caused by Thekopsora minima on blueberry (Vaccinium corymbosum) in South America. Plant Disease 103(5), p 1027.