Resumo

GUILLEN-CARVAJAL, María José; UMANA-ROJAS, Gerardina  e  VARELA-BENAVIDES, Ingrid. Colletotrichum species associated with anthracnose in orange (Citrus sinensis (L.) Osb.) and its in vitro control with fungicides. Agron. Mesoam [online]. 2023, vol.34, n.2, 52190. ISSN 2215-3608.  http://dx.doi.org/10.15517/am.v34i2.52190.

Introduction. Orange (Citrus sinensis (L.) Osb.) cultivation is one of the most important worldwide. Among the main limitations in its production is the fall of flowers caused by Colletotrichum. Objective. To determine the species of Colletotrichum associated with anthracnose in orange and to estimate the in vitro effectiveness of four fungicides on its control. Materials and methods. This study was carried out between June 2021 and February 2022. Six fungal isolates, obtained from orange floral tissues, were identified via polymerase chain reaction (PCR). The efficacy of the fungicides tebuconazole, pyraclostrobin, difenoconazole, and ferbam on two Colletotrichum isolates was evaluated. Two tests were carried out to determine the degree of inhibition of mycelial growth and the percentage of effectiveness of each fungicide. Results. Colletotrichum abscissum was identified on petals with symptoms and Colletotrichum gloeosporioides on calyxes. The effectiveness of the doses used of the fungicides tebuconazole and difenoconazole was verified by presenting inhibition of mycelial growth from a tenth of the commercial dose evaluated. Pyraclostrobin showed little control over both isolates. Ferbam did not present an efficient control in any of the doses evaluated in both strains. Conclusion. The fungi associated with anthracnose in orange, on the farm studied, were C. abscissum, present on petals with initial and advanced symptoms, and C. gloeosporioides present on persistent calyxes. The effectiveness of the fungicides evaluated was higher for triazoles, tebuconazole, and difenoconazole, in that order. Pyraclostrobin showed a poor control on both isolates. Ferbam was not effective in in vitro tests.

Palavras-chave : fungal diseases; citrus; pesticides.

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