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First Report of Anthracnose Caused by Colletotrichum gloeosporioides on Gueroba in Brazil

Gueroba (Syagrus oleracea (Mart.) Becc.), a member of the family Arecaceae, is an important native palm tree in central Brazil and has great potential as a cultivated crop and ornamental plant (1). In July 1999, anthracnose symptoms were observed on several gueroba plants growing in a field in Planaltina, Federal District. Leaves showed spots or small circular to irregular, brown-to-black necrotic lesions, which generally coalesced as symptoms progressed. Tissue sections from leaves with symptoms were plated aseptically on potato dextrose agar (PDA). A fungus was consistently isolated from leaves of symptomatic plants and was identified as Colletotrichum gloeosporioides (Penzig) Penzig & Sacc. by P. F. Cannon of CABI Bioscience, Egham, UK, where a culture (IMI 384186) has been deposited. An isolate was tested for pathogenicity by inoculating 20 plants at the two-leaf stage by placing a mycelial PDA plug from a 10-day-old fungal culture on a previously wounded leaf. Noninoculated plants served as controls. Plants were enclosed in a plastic bag and incubated for 4 days at 26 ± 2°C and ≈100% relative humidity. Ten days after inoculation, plants developed leaf lesions similar to those observed in the field. Symptoms did not develop on the control plants. C. gloeosporioides was reisolated from 95% of the inoculated leaves, completing Koch's postulates. The pathogenicity test was repeated with the same results. To our knowledge, this is the first report of C. gloeosporioides causing anthracnose on gueroba in Brazil.

Reference: (1) H. Lorenzi. Page 288 in: Árvores Brasileiras. Plantarum. Nova Odessa, Brazil 1998.