Epidemiology, damage assessment and integrated management of quiescent guava diseases

Abstract

One of the big problems in the marketing of guavas is the incidence of postharvest diseases, which coincides with the maturing of the fruits. The principal postharvest diseases that attack the guava are anthracnose (Colletotrichum gloeosporioides and C. acutatum) and black spot (Guignardia psidii). C. gloeosporioides and C. acutatum have similar temperature and moisture period requests for the fruit infection. A wide range of these variables was related to the disease incidence, which makes difficult the elaboration of forecasting systems like alternative to disease control. With regard to G. psidii, do not exist data about environmental requests for the infection, as well as there are not field works on the epidemiology for both diseases, not even for his control. The objectives of present project are 1) to determine the environmental variables required for the infection and the colonization of G. psidii in experiments with detached fruits; 2) to characterize spatial pattern and temporal dynamic of epidemics of these diseases in a 'Kumagai' white guava orchard and one of 'Pedro Sato' red guava; 3) to quantify the rot incidences in the wholesale markets of Campinas and São Paulo-SP; 4) to check the efficiency of atmosphere controlled using high doses of O2 combined with different doses of CO2 or N2O in the in vitro and in vivo control of postharvest diseases; 5) to determine the fungicide efficiency in the in vitro and in vivo control of postharvest cited diseases. To reach these objectives, experiments will be realized in controlled conditions, at ESALQ/USP and at APTA Bauru, and in a commercial orchard of white guava in Campinas and red guava in Itajú-SP, besides periodic liftings in the wholesale markets. (AU)