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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Resistance to citrus black spot by the analyses of disease progress curves

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Author(s):
Marcel B. Spósito [1] ; Renato B. Bassanezi [2] ; Lilian Amorim [3]
Total Authors: 3
Affiliation:
[1] Fundecitrus. Departamento Científico
[2] Fundecitrus. Departamento Científico
[3] USP. Escola Superior de Agricultura 'Luiz de Queiroz'. Departamento de Entomologia, Fitopatologia e Zoologia Agrícola
Total Affiliations: 3
Document type: Journal article
Source: Fitopatologia Brasileira; v. 29, n. 5, p. 532-537, 2004-10-00.
Abstract

Citrus (Citrus spp.) black spot, caused by Guignardia citricarpa, is responsible for serious damage to citriculture in the State of São Paulo. The main varieties of oranges (Citrus sinensis) in São Paulo are 'Hamlin', 'Pera', 'Valência' and 'Natal'. The literature suggests that late varieties such as 'Valência' and 'Natal' are most susceptible to citrus black spot, because these varieties are severely affected at harvest time. Nevertheless, there is no information about the temporal disease progress in the field. Resistance of the orange varieties 'Hamlin' (early), 'Pera' (mid-season), and 'Valência' (late) to citrus black spot was assessed in a commercial grove, under conditions of natural infection. Disease severity and disease incidence were assessed in 100 fruits of 100 plants of each variety, every 15 days, from the first appearance of symptoms in the field until harvest. The monomolecular model was fitted to the data of the disease progress curves for the three varieties. The rate parameter (r) of the disease progress curve was not different for the three varieties. Varieties 'Hamlin', 'Pera' and 'Valência' present the same degree of susceptibility to the MPC. (AU)