The research was carried out at the University of Costa Rica's phytopathology laboratory between October 1995 and March 1996. In an initial phase, some creole papaya fruits from Gu.cimo (Limón province) were used. In order to eliminate latent infections, they were washed and immersed in hot water (49° C for 20 minutes). The fruits were then randomly placed in groups of 20, which conformed each treatment. Finally, they were inoculated by spraying with 5.5 ml of a 10.000 Colletotrichum gloeosporioides spores per mililiter suspension; then they were placed in plastic boxes and stored in containers with a 30°C temperature and relative humidities of 70%, 80%, and 90%. Fruits were kept in the compartments for periods of 5, l0, 15, 20 and 25 hours. Temperature and relative humidity were monitored during the experiment through the incubator's sensors and with a portable hydrothermograph. Finally, the incidence and severity of anthracnose was evaluated. During the second phase, fruits of the Hawaiian sunrise variety were used, following the same procedures applied to the native fruits. In native fruits, 100% of those placed at 80% and 90% relative humidity were contaminated after being in the compartment for five hours. The incidence decreased in the group with 70% relative humidity. The damage level increased with increases in relative humidity, although some erratic behavior was observed. In the test with Hawaiian fruit, the disease incidence increased according with incubation time. Severity showed a similar behavour; however, there was also erratic behavour here.

The objective of this study was to determine the number of spores of fungi that cause diseases in the fruits of papaya and to measure the influence that petiole elimination could have on the population of disease propagating agents. The stems collected during the rainy season released a higher number (82%) of Colletotrichum sp. conidia than those collectedduring the dry season. In the stems collected during the rainy season a reduction was observed in the amount of conidia released (77%), between the first and the second week after collection. The stems collected during the dry and rainy season released a small amount of conidia after four weeks of collection. The higher numbers of Glomerella sp. ascospores captured during April to June. The capture of Colletotrichum sp. conidia with and without elimination of stems showed values that increased from April to June with a maximum between September and October. The numbers of disease propagating agents captured in the plots with and without stem elimination were similar for Glomerella sp. The elimination of stems caused a reduction in the number of spores captured in Colletotrichum sp., Helminthosporium sp. and Fusarium sp. fungi. Stem elimination caused no effect on Curvularia sp. and Alternaria sp. fungi. The rainy season was more favorable for the collection of spores of Helminthosporium sp., Curvularia sp. and Fusarium sp., compared to that from the dry season. For Alternaria sp. a higher number of spore was collected during the dry season.

The effect of several strategies - alone and integrated - on the control of the Phytophthora sp. fungae, which causes radical rotting of papaya fruits, was evaluated under nursery conditions. The experiment took place between August 1994 and March 1995 at the University of Costa Rica's Estación Experimental Fabio Baudrit, located in Alajuela, Costa Rica. The treatments applied were: sun heat for 30 days; organic fertilizer made from hen droppings; etridiazole fungicide; and the following combinations: sun heat + etridiazole + organic fertilizer; etridiazole + organic fertilizer; sun heat + etridiazole; sun heat + etridiazole + organic fertilizer, and finally, an inoculated control treatment. Soil rows were made, and then they were innoculated with the pathogenic agent, and finally the aforementioned treatments were applied. The treated soils were bagged separately. The Solo Sunrise Hawaiian variety was planted in bags. The percentage of gerrnination, stem diameter at soillevel, plant height, radical system fresh weight, and severity of radical rotting were evaluated three months later. In addition, the effect of the treatments on beneficent soil microorganism populations (actinomyces, protozoa, bacteria, and fungi) was evaluated, as well as those of pathogenic populations. Organic fertilizer increased plant strength. All treatments affected germination; the innoculated control had the greatest germination percentage. Treatments containing organic fertilizer affected germination most.