Psidium guajava-Guignardia psidii: inoculation methods and stages of susceptibility of fruits to black spot

Abstract

Brazil stands out as the world's main producer of guava, and the state of São Paulo has been included as the most important representative. However, post-harvest diseases of guava constitutes a dangerous obstacle for increasing production and marketing, as it interferes directly in the quality and quantity of the product. Amongst the post-harvest diseases of guava, the 'Black Spot' (Guignardia psidii) has been seen as the biggest of then. 'Black Spot' disease is characterized by the presence of rot in fruits caused by the fungus Guignardia psidii Ullasa e Rawal, which invalidate the consumption in natura. Due to the growing restriction to the use of fungicides in post-harvest and to the fact that regular application of fungicides increases the selection pressure on the pathogenic population, it's crucial to know satisfactorily the pathogenic system P. guajava-G. psidii, with aims to improve levels of control of the pathogen. So, studies about inoculation methods and stages of susceptibility of fruits with the 'Black Spot' becomes fundamental. Thus, the purpose of this work is to study the pathogenic system Psidium guajava-G. psidii in the context epidemiological of the 'Black Spot' of guava. To achieve that, it will determinate an inoculation method of G. psidii in fruits of guava from varieties Paluma and Pedro Sato, as well as the critic period of susceptibility of fruits. Certainly the results will contribute to understanding the pathogenic system P.guajava-G. psidii.