Temporal progress and spatial patterns of quiescent diseases in guava influenced by sanitation practices

  • Ivan Herman Fischer Agency Paulista Agribusiness Technology Regional Midwest Pole
  • Ana Raquel Soares-Colletti University of São Paulo/ESALQ; Dept. of Plant Pathology and Nematology
  • Maria Cecília de Arruda Palharini Agency Paulista Agribusiness Technology Regional Midwest Pole
  • Marise Cagnin Martins Parisi Agency Paulista Agribusiness Technology Regional Center South Pole
  • Lilian Amorim University of São Paulo/ESALQ; Dept. of Plant Pathology and Nematology
Keywords: Colletotrichum, Guignardia, Psidium guajava, postharvest fruit rot

Abstract

Postharvest diseases are a major problem in guava crops as the symptoms normally appear during fruit ripening. This study aimed to detect and characterize the temporal dynamics and spatial patterns of the most important guava diseases in orchards with and without removal of crop residues as a sanitation practice. The experiment was conducted in an orchard of ‘Pedro Sato’ guavas, over two consecutive seasons, and data were collected from the flowering to the fruit ripening stage. In immature guavas treated with paraquat and ethrel, Colletotrichum spp. was detected from the 5th day of incubation. Anthracnose was detected in flowers at incidences higher than 50 % and black spot in fruit larger than 5.5 cm in length. The monomolecular and the exponential models provided the best fit to anthracnose and black spot incidence progress curve data, respectively. Both diseases showed a predominantly random spatial pattern in the orchard. The removal of crop residues reduced the rate of disease progress in at least one season, and was effective in reducing the areas under the quiescent disease progress curves (AUDPC) of anthracnose. Anthracnose incidence increased from 57 to 96 % and black spot from 1 to 48 %, respectively, at fruit maturation levels 1 and 3. A negative correlation was found between disease incidence and the color of the fruit skin (°h). Fruit harvested during the later maturation stages showed higher incidence of the diseases. Due to the wide distribution and early infection of quiescent diseases, starting at flowering, preventive management should consider disease monitoring and removal of crop residues.

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Published
2017-02-01
How to Cite
Fischer, I., Soares-Colletti, A., Palharini, M., Parisi, M., & Amorim, L. (2017). Temporal progress and spatial patterns of quiescent diseases in guava influenced by sanitation practices. Scientia Agricola, 74(1), 68-76. https://doi.org/10.1590/1678-992x-2015-0425
Section
Plant Pathology