Incidência de danos pós-colheita em goiabas no mercado atacadista de São Paulo e sua relação com a prática de ensacamento dos frutos

The incidence of post harvest damages in guavas was quantified from April 2005 to August 2006 in four wholesalers from the terminal wholesale market of Sao Paulo (CEAGESP). The sampling was stratified by fruit size, fruit origin, flesh color and bagging the fruit. All fruit from 323 guava boxes were visually assessed. Post harvest mechanical injuries and diseases were quantified. Five thousand and eighty one fruit were assessed, 51.1% of which came from orchards where fruit received paper bags some time before harvesting. Post harvest mechanical injuries were observed in 63% of fruit but only 5.5% of fruit showed symptoms of post harvest diseases. These diseases incidence was correlated to the incidence of post harvest mechanical injuries only in bagged fruit (R=0.20, p< 0.05). These variables were not correlated in fruit not bagged (R=0.09). Black spot (Guignardia psidii) was observed in 3.5 % of fruit and anthracnose (Colletotrichum spp.), in 1.1 % of them. Post harvest rots caused by fungi from genera Fusicoccum, Rhizopus, and Pestalotia occurred in less than 1 % of fruit. The incidence of post harvest diseases caused by quiescent pathogens was significantly greater in bagged fruit (7.7 % of fruit) than in non-bagged fruit (2.1 % of fruit). The opposite was observed for wound-pathogens, with averages of 0.3 % and 0.8 % of symptomatic guavas for bagged and non-bagged fruit, respectively. There was no significant difference in the incidence of quiescent diseases in bagged fruit from varieties with white flesh (7.8 %) or red flesh (7.3 %).